Device for manufacturing spinal cord contusion model and injury testing method

Abstract

The invention relates to a device for manufacturing a spinal cord contusion model and a injury testing method, belongs to the field of spinal cord injury testing, and solves the technical problems that in the prior art, an instrument is complex in structure, large in size and high in cost, and the spinal cord contusion model manufactured by the instrument is not high in consistency and repeatability. The device for manufacturing the spinal cord contusion model can move, and the problem that a rat needs to be transferred in a spinal cord injury experiment due to the fact that an instrument is fixed is also solved. The device for manufacturing the spinal cord contusion model comprises a clamp mounting platform, an impactor mounting platform, an actuating transmission assembly, an impactor and a vertebra clamp, therefore, the movable base-plate-free device for manufacturing the spinal cord contusion model is formed.

Description

Technical Field

[0001] The present invention belongs to the field of spinal cord injury testing, and specifically relates to a device for making a spinal cord contusion model and an injury testing method, and more particularly to a device for making a spinal cord contusion model that is movable and has no bottom plate when making a spinal cord contusion model, and a device for making a new type of rat spinal cord contusion model that can avoid intraoperative rat transportation, firmly fix rat vertebrae, and accurately contuse the rat spinal cord. Background Art

[0002] In the research process of alleviating or curing traumatic spinal cord injury (SCI), the testing device for spinal cord injury plays an important role. The existing testing devices for rat spinal cord injury can be roughly divided into two categories according to the different control variables of the degree of injury: instruments that rely on force to control the degree of injury and instruments that rely on displacement to control the degree of injury. The most complete and representative instruments are Infinite Horizon (IH impact system) and New York University (NYU impact system). Figure 6 As shown in the figure, the IH impact system uses a pointed forceps (hereinafter referred to as IH clamp) with a shape similar to tweezers to clamp the rat vertebrae, and controls the impactor to set different impact forces to damage the spinal cord through a microprocessor and a servo motor, and returns the displacement or force parameters through a sensor; the NYU impact system uses a toothed forceps (hereinafter referred to as NYU clamp) to fix the rat vertebrae, and then releases a certain mass of weight from different heights to impact and contusion the spinal cord, and the impact speed is close to the terminal speed of the pure free fall process at the corresponding height.

[0003] When using the above-mentioned instruments to conduct spinal cord injury experiments, the vertebral clamp and the impactor are two important structures that affect the consistency and repeatability of the model, and both instruments have limitations.

[0004] First, the fixture: Although the above two impact systems can produce gradient spinal cord contusions with relatively obvious scoring differences in rats, it can be observed from the images recorded by the high-speed camera that the fixture has obvious shaking during the impact process. In addition, the fixtures of IH and NYU both have slight movements in the vertical direction, and the shaking of the fixtures interferes with the experimental results. This fixture shaking phenomenon will affect the repeatability of the contusion model, causing different substantial injuries and functional defects in models with the same injury grade.

[0005] The second is the impactor: IH uses the pressure feedback from the impactor as the basis for judging whether the impactor should continue to impact downward, which requires extremely sensitive and precise sensors and a rapid feedback system, has high requirements for the equipment, and the overall structure is complex and expensive; NYU directly releases heavy objects to impact the spinal cord, the impact time cannot be controlled, and the impactor bounces on the spinal cord, causing secondary contusion of the spinal cord.

[0006] In addition, the existing devices for making spinal cord injury models are all set to a fixed base or need to be fixed on a table. During the process of dissecting the rat's back and exposing the spinal cord, a special sterile heated operating table equipped with an anesthesia device is required to ensure the anesthesia and survival of the rat during the operation. When using the above-mentioned instruments to make spinal cord injuries, the rats that have completed the dissection and exposed the spinal cord need to be transferred during the operation from the sterile heated operating table to the spinal cord injury instrument. In this process, it is very difficult to maintain the anesthesia supply of the rat, avoid spinal cord compression, and avoid wound contamination. Summary of the invention

[0007] In view of the above problems, the present invention provides a device and an experimental method for making a spinal cord contusion model, which solves the technical problems in the prior art that the instrument has a complex structure, a large size, a high cost, and low consistency and repeatability in making a spinal cord contusion model. At the same time, the device for making a spinal cord contusion model of the present invention is movable, which also solves the problem of needing to transport rats in spinal cord injury experiments due to the fixation of the instrument.

[0008] The present invention provides a device for making a spinal cord contusion model, comprising a fixture mounting platform, a striker mounting platform, an actuating transmission assembly, a striker and a vertebral fixture; forming a mobile bottom-free device for making a spinal cord contusion model;

[0009] The striker mounting platform and the vertebral fixture are arranged on the fixture mounting platform;

[0010] The actuating transmission assembly is arranged on the striking device mounting platform, the striking device is arranged on the actuating transmission assembly, and the actuating transmission assembly is used to drive the striking device;

[0011] The vertebral clamp is used to clamp the vertebrae of the animal to be tested, and the impactor is used to impact the object to be tested to make a spinal cord contusion model;

[0012] Determine the constraint conditions of the gravity component of the device used to make the spinal cord contusion model in the direction perpendicular to the device's equivalent lever for rotation;

[0013] The deadweight of the device is determined based on the constraint conditions and the component of the gravity of the device in a direction perpendicular to the rotational equivalent lever of the device.

[0014] Optionally, the fixture mounting platform is a fixture mounting bracket, which is used to adjust the striker mounting platform in three translational degrees of freedom of x, y and z axes.

[0015] Optionally, the striker mounting platform is used to provide adjustment of the y-axis translational freedom of the actuating transmission assembly.

[0016] Optionally, the actuating transmission assembly is used to provide adjustment of the z-axis translational freedom for the driven striker.

[0017] Optionally, the vertebral clamp is arranged on the clamp mounting platform so as to be translatable along the y-axis.

[0018] Optionally, the fixture mounting platform includes an x-axis moving assembly, a y-axis moving assembly, and a z-axis moving assembly.

[0019] Optionally, the expression for determining the constraint condition of the gravity component of the device for making the spinal cord contusion model in the direction perpendicular to the device rotation equivalent lever is:

[0020]

[0021] Among them, F impact F represents the spinal cord contusion force applied by the impactor; mg is the component of the gravity of the device used to make the spinal cord contusion model in the direction perpendicular to the equivalent lever of the device rotation; H is the projection distance between the vertebral clamp and the bottom of the x-axis moving component on the y-axis; L is the distance between the vertebral clamp and the end of the x-axis moving component on the x-axis; ΔL is the projection distance between the vertebral clamp and the center line of the z-axis moving component on the x-axis.

[0022] Optionally, the actuating transmission assembly includes a steering gear, a gear and a rack, the steering gear provides power, and the gear and the rack transmit the power of the steering gear to the striker to drive the striker to move.

[0023] Optionally, the striker includes a striker tip and an x-axis translation freedom driving mechanism, and the x-axis translation freedom driving mechanism is used to give the striker tip an x-axis translation freedom.

[0024] Another aspect of the present invention further discloses a method for testing spinal cord contusion, which comprises the following specific steps:

[0025] Using the aforementioned device for making a spinal cord contusion model, a spinal cord contusion is made on the test animal;

[0026] The wound of the rat back with spinal cord contusion was sutured;

[0027] The rats with back wound sutured were evaluated for ground hind limb movement within a set time to obtain the recovery of hind limb movement function after spinal cord injury.

[0028] The injured spinal cord of rats was sampled and processed to obtain sections stained with chrome cyanine EC;

[0029] The sections stained with chrome cyanine EC were subjected to histological analysis to obtain the extent of spinal cord injury and preserved tissue;

[0030] The volume of injury and preserved tissue of the sections stained with chrome cyanine EC were obtained;

[0031] Based on the extent of injury to the spinal cord, measurements of injury extent and volume as well as the percentage of preserved tissue are obtained.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] 1. The fixture installation platform of the present invention is a gantry structure with three degrees of freedom. The three sets of guide rails can conveniently realize the precise positioning of the fixture in the experimental space. At the same time, the fixed end beam structure composed of a pair of parallel screw guide rails and a crossbeam can greatly improve the stability of the fixture, ensuring that the fixture does not shake during the spinal cord contusion experiment.

[0034] 2. The striker mounting platform of the present invention is mounted on the crossbeam of the fixture mounting platform, and can achieve a wide range of displacement adjustment along with the adjustment of the fixture mounting platform, thereby reducing the pressure of self-adjustment and positioning, and also improving the integration and use efficiency of the instrument.

[0035] 3. The present invention is a movable structure as a whole, and can be removed or placed on the rat surgical platform at any time as needed. The bottom of the present invention uses a pair of parallel screw guide rails of specific weight as a support base, and does not require a bottom plate or a special desktop for fixed support. The deadweight of the three sets of guide rails and the rubber pads under the bottom guide rails can ensure the stability of the instrument during use, thereby improving the stability of the fixture.

[0036] 4. The striker of the present invention adopts a self-designed micro precision slide rail assembly and a high-precision linear ball bearing as its internal support structure, which can provide the striker tip with adjustable freedom while ensuring that the striker tip maintains sufficient stability during the process of impacting the spinal cord without bouncing or shaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a front view of the device for making a spinal cord contusion model of the present invention;

[0038] Figure 2 A front view of a vertebral clamp of the device for making a spinal cord contusion model of the present invention;

[0039] Figure 3 It is a front view of the striking device mounting platform of the device for making a spinal cord contusion model of the present invention;

[0040] Figure 4 It is a front view of the actuating transmission assembly of the device for making a spinal cord contusion model of the present invention;

[0041] Figure 5 It is a front view of the striking device of the device for making a spinal cord contusion model of the present invention;

[0042] Figure 6 (a) and (b) are the IH fixture impact system and the NYU fixture impact system in the prior art respectively;

[0043] Figure 7 It is a side view of the device for making a spinal cord contusion model according to the present invention.

[0044] Reference numerals:

[0045] 1- fixture mounting platform, 2- striker mounting platform, 3- actuator transmission assembly, 4- striker, 11- x-axis first guide rail base, 12- x-axis first guide rail slider, 13- x-axis hand crank handle, 14- crossbeam, 15- z-axis moving synchronous wheel, 16- z-axis moving synchronous belt, 17- z-axis moving locking component, 18- first guide rail slider, 19- first guide rail base, 20- fixture mounting bracket, 21- vertebral fixture, 22- third guide rail handle, 23- third guide rail slider, 24- third guide rail base, 25- x-axis second guide rail base, 26- x-axis second guide rail slider, 27- z-axis hand crank handle, 28- x-axis moving synchronous belt, 29- x-axis moving locking component, 30- x-axis moving synchronous wheel, 32- universal support rod, 33- Cross guide rail connector, 34-slide rail, 35-actuator transmission assembly mounting bracket, 36-servo, 37-gear, 38-rack, 39-second guide rail slider, 40-second guide rail base, 49-striker tip, 50-striker base, 51-mini slider, 52-cover plate, 53-high head knurled hand screw bolt, 54-mini guide shaft, 55-M3 hexagonal nut, 56-mini ball bearing, 57-mini linear guide, 58-mini slider, 59-M3 hexagonal nut, 60-M3 hexagon socket bolt, 61-M3 hexagonal nut, 62-high precision force sensor, 70-z-axial first guide rail base, 71-z-axial first guide rail slider, 72-z-axial second guide rail base, 73-z-axial second guide rail slider, 74-x-axis moving assembly end. DETAILED DESCRIPTION

[0046] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. In addition, the present invention can also be implemented in other ways different from those described herein, and therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0047] A specific embodiment of the present invention, as Figure 1-Figure 6 , discloses a device for making a spinal cord contusion model, including a clamp mounting platform 1, a striker mounting platform 2, an actuating transmission assembly 3, a striker 4, a vertebral clamp 21 and a control system.

[0048] Among them, the vertebral clamp 21 and the striker mounting platform 2 are arranged on the clamp mounting platform 1; the actuating transmission assembly and the striker are arranged on the striker mounting platform 2; a control box is also arranged on the clamp mounting platform 1 for controlling the movement of the striker and receiving the measurement data of the high-precision force sensor.

[0049] The fixture installation platform 1 is a fixture installation bracket; the striker installation platform 2 includes a striker installation bracket;

[0050] Preferably, the fixture mounting bracket is a gantry structure composed of three sets of screw guide rails, which are responsible for adjusting the three translational degrees of freedom of the x, y and z axes respectively, so as to realize any positioning of the fixture in the operating space, and a rubber pad is attached under the bottom set of screw guide rail bases to provide anti-slip and buffering and shock absorption functions. In addition, the fixture mounting platform 1 also has the function of installing the striker mounting platform, which improves the integration of the instrument while reducing the difficulty of instrument operation.

[0051] The striker mounting platform 2 is used to mount the actuating transmission assembly 3 and the striker 4. The striker mounting platform 2 is mounted on the crossbeam 14 of the fixture mounting platform 1, and can be used to adjust a wide range of spatial positions in space. The striker mounting platform 2 has two screw guide rails, which are arranged crosswise to form a cross guide rail group, which has translational freedom in the y and z axis directions, and provides the striker 4 with two vertical adjustment functions.

[0052] like Figure 4 As shown, the actuating transmission assembly 3 includes a steering gear 36, a gear 37 and a rack 38. The steering gear 36 provides power, and the gear 37 and the rack 38 transmit the power of the steering gear 36 to the striker 4 to drive the striker to move.

[0053] The gear 37 is connected to the steering gear 36 and then fixed to the actuating transmission assembly mounting bracket 35 . The rack 38 is fixed to the striker base 50 . The steering gear and the striker are driven by the gear 37 and the rack 38 .

[0054] like Figure 5 As shown, the appearance and internal components of the striker 4 are shown. In order to prevent the striker tip 49 from swinging or jumping during the striking process, while providing the striker tip 49 with adjustable freedom, the striker 4 of the device for making a spinal cord contusion model of the present invention adopts a self-designed micro-precision slide rail group and a high-precision linear ball bearing as its internal support structure, which can ensure that the striker tip 49 maintains sufficient stability during the process of impacting the spinal cord. Specifically, the striker 4 includes a striker base 50, a slider 51, a cover plate 52, a striker tip 49 and a high-head knurled hand-tightening bolt 53; a mounting chamber is arranged at the end of the striker base 50, and a micro guide shaft 54, a micro linear guide rail 57, a micro slider 58, a micro ball bearing 56, an M3 hexagon socket bolt 60, an M3 hexagon nut 55 and an M3 hexagon nut 59 are arranged in the mounting chamber; the cover plate 52 is connected to the outside of the fixed striker base 50 by an M3 hexagon socket bolt 60 and an M3 hexagon nut 61 with a length of 20 mm; two micro guide shafts 54 are fixed between the striker base 50 and the cover plate 52; a micro linear guide rail 57 and a pair of symmetrical M3 hexagon nuts 59 are fixed on the micro slider 58, which can be moved along the micro guide shaft 54 Sliding; the hand-tightening bolt 53 passes through a pair of miniature ball bearings 56 fixed at corresponding positions of the striker base 50 and the cover plate 52, and is locked and fixed by the M3 hexagonal nuts 55 at both ends. At this time, the hand-tightening bolt 53 is relatively fixed to the inner ring of the miniature ball bearing 56, and can still rotate freely relative to other parts; the M3 hexagonal nut 59 on the miniature slider 58 is engaged with the hand-tightening bolt 53, and the miniature slider 58 can be moved along the miniature guide shaft 54 ​​by rotating the hand-tightening bolt 53, and the adjustable range is 10mm; the striker tip 49 is set at the lower end of the miniature slider 58 through a high-precision force sensor 62. By rotating the hand-tightening bolt 53, the striker tip 49 can move on the miniature guide shaft 54 ​​with the miniature slider 58, and is given an x-axial translational degree of freedom.

[0055] like Figure 3 As shown, the cross guide rail set of the striker mounting platform 2 and the micro guide rail embedded in the striker 4 itself together provide three translational degrees of freedom for the striker tip 49, so that the striker tip 49 has the ability to be arbitrarily positioned in the operating space, and the adjustable ranges in the three directions of x, y and z are 10mm, 100mm and 40mm respectively.

[0056] Furthermore, the fixture installation platform 1 is designed as a movable gantry structure of a simply supported beam structure, including an x-axis moving component, a y-axis moving component and a z-axis moving component.

[0057] Preferably, the x-axis moving assembly includes an x-axis first guide rail base 11, an x-axis second guide rail base 25, an x-axis first guide rail slider 12, an x-axis second guide rail slider 26, an x-axis hand crank 13, an x-axis moving synchronous belt 28 and an x-axis moving locking component 29;

[0058] The first x-axis guide rail base 11 and the second x-axis guide rail base 25 both include guide rails, guide rail frames and screw rods; the first x-axis guide rail slider 12 and the second x-axis guide rail slider 26 are respectively arranged on the screw rods of the first x-axis guide rail base 11 and the second x-axis guide rail base 25; the x-axis hand crank handle 13 is arranged at one end of the first x-axis guide rail base 11, and the x-axis moving locking component 29 is arranged at the same side end of the second x-axis guide rail base 25; the x-axis moving synchronous belt 28 connects the x-axis hand crank handle 13 and the x-axis moving locking component 29 through a pair of x-axis moving synchronous wheels 30. By rotating the x-axis hand crank handle 13, the first x-axis guide rail slider 12 and the second x-axis guide rail slider 26 can move on the first x-axis guide rail base 11 and the second x-axis guide rail base 25, and the movable range is 200mm.

[0059] Preferably, the z-axis moving assembly includes a z-axis first guide rail base 70, a z-axis second guide rail base 72, a z-axis first guide rail slider 71, a z-axis second guide rail slider 73, a z-axis hand crank handle 27, a z-axis moving synchronous belt 16 and a z-axis moving locking component 17;

[0060] The first z-axis guide rail base 70 and the second z-axis guide rail base 72 both include guide rails, guide rail frames and screw rods; the first z-axis guide rail slider 71 and the second z-axis guide rail slider 73 are respectively arranged on the screw rods of the first z-axis guide rail base 70 and the second z-axis guide rail base 72; the z-axis hand crank handle 27 is arranged at one end of the first z-axis guide rail base 70, and the z-axis moving locking component 17 is arranged at the same side end of the second z-axis guide rail base 72; the z-axis moving synchronous belt 16 connects the guide rail hand crank handle 27 and the z-axis moving locking component 17 through a pair of z-axis moving synchronous wheels 15. By rotating the z-axis hand crank handle 27, the first z-axis guide rail slider 71 and the second z-axis guide rail slider 73 can move on the first z-axis guide rail base 70 and the second z-axis guide rail base 72, and the movable range is 200mm.

[0061] Preferably, the z-axis moving assembly includes a crossbeam 14, a third guide rail handle 22, a third guide rail slider 23, and a third guide rail base 24;

[0062] The crossbeam 14 is fixed on the first z-axis guide rail slider 71 and the second z-axis guide rail slider 73, and is provided with double rows of guide grooves; the upper guide groove is used for detachably installing the first guide rail base 19 and the universal support rod 32 of the striker mounting platform 2, and the lower guide groove is used for fixing the third guide rail base 24; the third guide rail base 24 is provided with a guide rail, a guide rail frame and a screw rod, and the third guide rail slider 23 is provided on the screw rod of the third guide rail base 24, and can be adjusted and moved by the third guide rail handle 22, and the movable range is 100 mm.

[0063] Preferably, the projection distance between the vertebral clamp 21 and the bottom of the x-axis moving component on the y-axis is H, the distance between the vertebral clamp 21 and the end 74 of the x-axis moving component on the x-axis is L, preferably, L≈100mm, and the projection distance between the vertebral clamp 21 and the center line of the z-axis moving component on the x-axis is ΔL, preferably, ΔL≈20mm.

[0064] Furthermore, when the spinal cord is impacted by external force, the device is subjected to a clockwise ( Figure 7 ) of the rotation torque M1, at this time, the device is equivalent to a linear lever connecting the vertebral clamp 21 and the bottom of the end of the x-axis moving component, and the fixed fulcrum is the bottom of the end of the x-axis moving component. This lever is called the device rotation equivalent lever ( Figure 7 (shown by the thick dashed line in the side view of the device).

[0065] Determine the gravity of the device used to make the spinal cord contusion model perpendicular to the device's equivalent lever ( Figure 7 The component force F in the direction indicated by the thick dashed line in the side view of the device mg The constraint condition is expressed as:

[0066]

[0067] Among them, F impact F represents the spinal cord contusion force applied by the impactor; mg It is the component of gravity G of the device used to make a spinal cord contusion model in the direction perpendicular to the equivalent lever of the device rotation.

[0068] Specifically, F impact The force exerted by the striker tip 49 to injure the spinal cord is shown.

[0069] Preferably, the force F that injures the spinal cord impact The maximum shall not exceed 50N.

[0070] Furthermore, the gravity component F of the device for making a spinal cord contusion model in the direction perpendicular to the equivalent lever of the device rotation is mg The expression is:

[0071]

[0072] Where m is the weight of the device used to make the spinal cord contusion model, θ is the mg Force F in the xz plane mg The angle with the z-axis; g represents the acceleration due to gravity.

[0073] Furthermore, based on formulas (1) and (2), the deadweight m of the device used to make the spinal cord contusion model is obtained, which is expressed as:

[0074]

[0075] Preferably, m≥10 kg.

[0076] Preferably, the constraint conditions of the total weight m2 of the x-axis moving assembly and the z-axis moving assembly, a total of 4 sets of screw guide rails, and the self-weight m1 of the remaining components of the device for making a spinal cord contusion model are determined, and the expression is:

[0077] m=m1+m2;

[0078] m1g·ΔL< <m2g·L*(4)

[0079] Wherein, L* is the distance between the end of the z-axis moving component and the end of the x-axis moving component.

[0080] Furthermore, based on the divisor conditions of the total weight m2 of the 4 sets of screw guides including the x-axis moving assembly and the z-axis moving assembly and the deadweight m1 of the remaining components of the device for making a spinal cord contusion model, and the deadweight m of the device for making a spinal cord contusion model, the weight distribution of the total weight m2 of the 4 sets of screw guides including the x-axis moving assembly and the z-axis moving assembly and the deadweight m1 of the remaining components of the device for making a spinal cord contusion model is obtained.

[0081] For example, L*≈100 mm, ΔL≈40 mm,

[0082] at this time,

[0083] set up

[0084]

[0085] Preferably, m2 ≥ 8 Kg, m1 ≤ 2 Kg.

[0086] Further, see Appendix Figure 3The striker mounting platform 2 is mounted on the upper guide groove of the crossbeam 14 of the z-axis moving assembly; the striker mounting platform 2 includes a first guide rail slider 18, a first guide rail base 19, a second guide rail slider 39, a second guide rail base 40, a universal support rod 32, a cross guide rail connector 33, a slide rail 34 and an actuating transmission assembly mounting bracket 35; the universal support rod 32 is arranged at both ends of the first guide rail base 19; the first guide rail slider 18 is arranged on the first guide rail base 19, and the adjustable moving range is 100mm;

[0087] One side of the cross guide connector 33 is arranged on the first guide slider 18, and the first guide slider 18 drives the cross guide connector 33 to move along the y-axis; the other side of the cross guide connector 33 is arranged on the second guide base 40, and the second guide base 40 is provided with a guide rail and a screw rod, and the second guide slider 39 is slidably arranged on the screw rod, and the adjustable movement range is 40mm; one side of the actuating transmission assembly mounting bracket 35 is arranged on the second guide slider 39, and the second guide slider 39 can drive the actuating transmission assembly mounting bracket 35 to move along the z-axis, and the other side of the actuating transmission assembly mounting bracket 35 is connected to the slide rail 34.

[0088] Further, see Appendix Figure 4 , the actuation transmission assembly includes a servo 36, a gear 37 and a rack 38; the servo 36 is connected to the gear 37, and the gear 37 is connected to the rack 38; the striker base 50 is arranged on the rack 38 and is slidably connected to the slide rail 34; the servo 36 drives the gear 37 to rotate, the gear 37 drives the rack 38 to run, and the rack 38 drives the striker base 50 to move along the z-axis direction. The servo model used in this device is a single-axis ZX20S, which outputs torque through a single output shaft, can provide a maximum torque of T = 20kg·cm, a rotation accuracy of 0.24°, and a maximum response speed of ω = 60° / 0.16s (375° / s); the gear module m = 1, the number of teeth n = 30, the pitch circle diameter d1 = m×n = 30mm; the rack module is also 1.

[0089] Furthermore, the distance between the center axis of the striker tip 49 and the center axis of the output shaft of the steering gear 36 is l, and the size of l is adjusted by the high-head knurled hand-tightening bolt 53, l∈[25,35]mm; the maximum output force of the striker tip 49 is Wherein, T represents the maximum torque that the servo can provide, preferably, 20 kg·cm; g represents the gravitational acceleration constant, preferably, 9.8 N / kg;

[0090] Further, the maximum operating speed of the striker tip 49 is Among them, ω represents the maximum angular velocity of the servo response; d1 represents the pitch circle diameter.

[0091] The vertebral clamp 21 is arranged on the clamp mounting bracket 20 , and the clamp mounting bracket 20 is connected to the third guide rail slider 23 , and the third guide rail slider 23 is on the screw rod of the third guide rail base 24 .

[0092] The main chip of the control system is Atmel Mega328P, and 5 external control buttons are connected to control the operation of the servo 36; the 5 buttons have different functions:

[0093] Key 1 and key 2 are responsible for the "preset" and "zeroing" functions of the striker. Under the "preset" function, the servo 36 rotates clockwise to make the striker tip 49 reach a specific position close to the spinal cord. This position is controlled by the parameter setting in the programming. The "zeroing" function is opposite to the "preset" function. The servo 36 is controlled to rotate counterclockwise to make the striker tip 49 reach the farthest distance from the spinal cord. During the braking process, when the speed is high, the servo usually has an overtravel phenomenon due to its own inertia, that is, it rotates beyond the preset position and then reverses to adjust to the preset position. In the above-mentioned "preset" and "zeroing" unidirectional displacement process, in order to avoid the interference of the overtravel displacement to the experiment, a two-stage displacement control is adopted. In the first stage of control, the servo 36 rotates to move the striker tip 49 to 1mm away from the target position, and then the second stage of control is immediately started to make the striker tip 49 continue to move 1mm, and finally it can accurately move to the target position to avoid the interference of the overtravel phenomenon to the experiment.

[0094] Button 3 and button 4 are responsible for adjusting the strike depth x, x∈[0.5,2.5]mm. Press button 3 to increase x, and press button 4 to decrease x. Each adjustment increases / decreases by 0.1mm. This function provides users with more selectable damage gradients and more precise damage control.

[0095] Button 5 controls the "strike" function of the striker. After completing the setting of the strike depth and positioning of the striker tip 49, pressing button 5 starts the "strike" process. In order to make the striker tip 49 have a higher instantaneous injury rate during the contusion of the spinal cord, the "strike" process innovatively adopts a three-stage design, which is lifting, contusion, and resetting in order. In the lifting stage, the servo 36 rotates counterclockwise to lift the striker tip 49 by 10 mm; in the contusion stage, the servo 36 rotates clockwise to move the striker tip 49 downward by (10+x) mm, causing a damage to the spinal cord with a depth of x mm; in the resetting stage, in order to prevent the striker tip from staying and causing secondary damage to the spinal cord, the servo 36 quickly rotates counterclockwise after the contusion is completed, and lifts the striker tip 49 to 20 mm away from the spinal cord.

[0096] This device uses a high-precision steering gear as a driving component, and uses a gear rack set to convert the rotation process into a linear motion process. In this process, the steering gear 36 turns an angle It has a linear mapping relationship with the striking depth x of the striking device tip 49, and its functional relationship expression is: That is, by manipulating the steering gear 36 to rotate the corresponding angle That is, the striker tip 49 can be moved to the preset striking depth x.

[0097] The device uses a high-precision force sensor 62 as a data acquisition device, which is an S-type tension and compression sensor with a measuring range of 100N and a measurement accuracy of 0.05%. It is directly connected to a computer through a connected data acquisition card to achieve wireless real-time transmission and storage of data.

[0098] In addition, the control system of this device has reserved additional servo interfaces and A4988 chip sockets, and other functions can be expanded later.

[0099] Furthermore, the present invention also discloses another implementation mode, using a 42 stepper motor or a 57 stepper motor to drive the screw to rotate, connecting the motor output shaft to the guide rail screw through a coupling, and then controlling the motor operation through chips such as A4988 to complete the adjustment of the guide rail spatial position.

[0100] Furthermore, the present invention also discloses another embodiment, which uses a more expensive and more precise servo motor as a driving component, striving to achieve higher accuracy and faster speed.

[0101] Furthermore, the present invention also discloses another embodiment, using a gear 37 with 1 module and 30 teeth and a rack 38 with 1 module as the transmission parts, the impact speed of the tip of the striker can reach about 100mm / s. The improvement scheme can replace the gear rack group with different numbers of teeth to achieve the effect of changing the impact speed of the tip of the striker; for example, the number of gear teeth is reduced, when the gear module m=1, the number of teeth n2=20, the pitch circle diameter of the gear is d2=m×n=20mm, and the maximum running speed of the tip of the striker 49 is

[0102]

[0103] Another aspect of the present invention provides an experimental method for spinal cord contusion, wherein the spinal cord contusion is produced using the aforementioned device for producing a spinal cord contusion model, and the specific steps are:

[0104] During the experiment using the device, the fixture mounting platform is used to support and position the vertebral fixture, the vertebral fixture 21 is used to fix the vertebrae, the striker mounting platform is used to support and position the striker and the actuating transmission assembly, the striker tip 49 is used to contusion the spinal cord, and the actuating transmission assembly is used to provide power to the striker;

[0105] In addition, this experimental process also involves the use of a rat stereotaxic apparatus and other surgical instruments, among which the rat stereotaxic apparatus is a rat dissection operating table;

[0106] In particular, the use of a high-speed camera is also included in the experimental process. When the spinal cord is injured, the high-speed camera is aligned parallel to the rat stereotaxic instrument and placed on a tripod at a distance of 50 cm. The full-frame (1 million pixels) shooting rate of the high-speed camera is ≥ 12,600 frames per second; the maximum shooting rate is not less than 550,000 frames per second, the sensitivity is 100,000 black and white, and the cache DRAM is ≥ 72GB. The dynamic image of the spinal cord changes at the moment of spinal cord injury is captured by the high-speed camera, and the observer is projected frame by frame based on the video recording to observe the relative movement between the vertebral clamp 21, the clamp mounting bracket 20, and the striker tip 49 within the field of view during the injury process.

[0107] Step S1, selecting rat individuals suitable for making a spinal cord contusion model. The experimental individuals in the same group should be of the same gender, similar weight, and similar body shape. Usually, 300 g male rats are selected as experimental individuals.

[0108] Step S2, anesthetize the experimental individual with chloral hydrate, place it in a rat stereotaxic instrument, and fix the rat's head with a mask and ear bars; use a razor to remove the back and surrounding mouse hair corresponding to the T8-T11 vertebrae to complete the skin preparation operation; dissect the rat to expose the T8-T11 segmental vertebrae of the rat, remove the T9 vertebral lamina and the T8 vertebral spinous process, and expose the spinal cord;

[0109] Step S3, fix the vertebral clamp 21 to the groove between the transverse process and the facet joint of the T9 vertebra and the T10 vertebra. At this time, the clamp position can be observed with a surgical microscope to ensure that the clamp is fully clamped; during the bolt tightening process, use a torque screwdriver to tighten the clamp to 2.7N / cm to ensure a consistent grip and prevent over-tightening;

[0110] Step S4, rotating the x-axis hand crank handle 13 in the device, so that the x-axis first guide rail slider 12 and the x-axis second guide rail slider 26 are synchronously moved along the screw rods of the x-axis first guide rail base 11 and the x-axis second guide rail base 25 to the position where the screw rods are close to the x-axis hand crank handle 13; rotating the z-axis hand crank handle 27 in the device, so that the z-axis first guide rail slider 71 and the z-axis second guide rail slider 73 are synchronously moved along the screw rods of the z-axis first guide rail base 70 and the z-axis second guide rail base 72 to the position where the screw rods are close to the z-axis hand crank handle 27; at this time, the device is in the initial state of use;

[0111] Step S5, transfer the device to the top of the rat stereotaxic instrument, so that the first x-axis guide base 11 and the second x-axis guide base 25 are placed on both sides of the rat stereotaxic instrument, and the rat's head is facing the x-axis hand crank handle 13; adjust the x-axis hand crank handle 13 and the z-axis hand crank handle 27 to make the fixture mounting bracket 20 close to the vertebral fixture 21 on the x and z axes; adjust the small guide handle 22, and the third guide slider 23 moves along the third guide base 24 to make the fixture mounting bracket 20 close to the vertebral fixture 21 on the y axis; use a torque screwdriver to tighten the fixing bolts between the mounting holes to fix the vertebral fixture 21 to the fixture mounting bracket 20; lock the x-axis moving locking component 29 and the z-axis moving locking component 17 to lock the position of each slide slider, and the vertebral fixation of the rat experimental part is completed.

[0112] Step S6, adjust the first guide rail slider 18 in the striker mounting platform 2 by the small guide rail rotary handle, and adjust the micro slider 58 by the high-head knurled hand screw 53, so that the striker tip 49 is facing the exposed spinal cord in the x and y axes (in a top view); use the control system button 1 to make the striker tip 49 reach the preset position; adjust the positioning of the second guide rail slider 39 by rotating the small guide rail rotary handle of the second guide rail, so that the lower end of the striker tip 49 drops to just contact the exposed spinal cord surface; the positioning of the striker tip 49 is now completed. The data acquisition card of the high-precision force sensor 62 is wirelessly connected to the computer, and the data acquisition system is turned on to prepare to collect the force parameters of the striker tip during the spinal cord contusion process.

[0113] Step S7, according to the experimental requirements, use the buttons 3 and 4 of the control system to set the striking depth x, where x∈[0.5,2.5]mm; press button 5 to complete the "strike" process; in this process, a high-speed camera is used to capture the dynamic image of the spinal cord changes at the moment of spinal cord contusion injury, and the observer plays it frame by frame based on the video recording, so as to observe the relative movement between the vertebral clamp 21, the clamp mounting bracket 20 and the striker tip 49 within the field of view during the injury process, and quantitatively evaluate their effectiveness. After the process is completed, the striker tip 49 stays at 20mm from the spinal cord surface;

[0114] Step S8, use button 2 to move the striker tip 49 away from the spinal cord to the "zero" position, and release the connection between the vertebral clamp 21 and the clamp mounting bracket 20; adjust the x-axis hand crank handle 13 and the z-axis hand crank handle 27 to move the clamp mounting bracket 20 away from the vertebral clamp 21; move the device away from the rat stereotaxic instrument, remove the vertebral clamp 21 and suture the rat's back wound, and the experiment is completed.

[0115] Step S9, the data of force parameters collected during the experiment are stored and imported into MATLAB, the useless data at the beginning and end of the data set are removed, the force image of the striking process is drawn, and the maximum force value in the contusion process is found through the max function. The striking displacement is matched with the maximum force value one by one, and the variance S of the maximum force value under the same striking displacement is calculated to count the repetition rate of the device of the present invention.

[0116] Step S10, continuously evaluating the ground hind limb movement of the injured rat within 2 months after the back wound of the rat is sutured, so as to obtain the recovery of the hind limb movement function of the rat after spinal cord injury.

[0117] Specifically, the Basso, Beattie, and Bresnahan motor scoring scale (BBB score) was used to score the motor recovery of the experimental rats on the 7th, 14th, 21st, 28th, 35th, 42nd, 49th, and 56th days after suture of the rat back wound, and the score was plotted as a function of BBB score-time t. Analysis of variance was used to study the differences between rats with spinal cord injury with different degrees of injury or different postoperative treatments. The significance standard for the differences between different experimental groups was set to 0.05. When the significance level p<0.05, it was considered that there were differences between the groups.

[0118] Step S11, sampling and processing the injured spinal cord of the rat to obtain chromocyanine (EC) stained sections.

[0119] Specifically, rats were anesthetized by an overdose of sodium pentobarbital and then perfused cardiacally with 0.1 M phosphate buffered saline (PBS, pH 7.4), followed by perfusion with PBS mixed with 4% paraformaldehyde (PF).

[0120] Furthermore, in order to maintain the consistency of sampling, each spinal cord was transected at the spinal nerve root of the thoracic T6 segment of the sample, and a 3-cm-long spinal cord segment was dissected backwards and fixed in paraformaldehyde PF at 4°C for 2 hours, and then placed in 20% sucrose / PBS at 4°C for cryoprotection. The spinal cord was serially frozen and sectioned to 20 mm and mounted on gelatin-coated slides. Chrome cyanine (EC) is a dye that can bind to specific components in tissues. In spinal cord tissue, it can stain structures such as myelin sheaths, thereby distinguishing white matter from cell bodies. White matter mainly contains nerve fibers and myelin sheaths. After staining, the range and morphology of white matter can be clearly displayed; for the cell body part, staining can help observe the condition of neuronal cell bodies, such as their changes in number and morphology after spinal cord injury. The obtained spinal cord sections were stained using the EC staining protocol to obtain EC-stained sections, so as to subsequently calculate the amount of retained tissue in the transverse axial sections of the injured spinal cord; the retained tissue refers to tissue that is considered to be functionally normal based on positive myelin staining or gray matter cell structure similar to that of the control group sections.

[0121] Step 12: Perform histological analysis on the EC stained sections to determine the spinal cord injury center and preliminarily obtain the extent of spinal cord injury.

[0122] Specifically, the image analysis software NIH Image v 1.62 (NIH, Bethesda) was used to perform image analysis on each group of EC stained sections, and the area of ​​the retained tissue in the gray matter and white matter in the image and the area of ​​the total stained tissue (including gray matter, white matter and other stainable tissues) were obtained respectively; the area of ​​lesion tissue can be calculated by subtracting the area of ​​retained tissue from the total tissue area, and the lesion center of each spinal cord can be determined based on the area of ​​lesion tissue; the area of ​​lesion tissue at the lesion center of the spinal cord can be divided by the total stained tissue area to obtain the degree of spinal cord injury.

[0123] Specifically, the above image analysis steps were all performed under a double-blind method.

[0124] It is understood that the tissue at the center of each spinal cord lesion is the slice in which the percentage of lesion tissue to total stained tissue is the largest.

[0125] Step 13, obtaining the damaged volume and the volume of the retained tissue of the EC-stained sections.

[0126] Specifically, the total volume of injured tissue, including the volume of gray matter, white matter, and total tissue preserved in the injured spinal cord, was calculated from a series of evenly distributed EC-stained sections using the Cavalieri method.

[0127] Furthermore, when calculating tissue preservation at the injury site, the cross-sectional area correction factor (CF) obtained from the intact distal spinal cord tissue is considered to avoid the problem of difficulty in accurately measuring the pre-injury volume required for tissue preservation due to tissue shrinkage caused by the injury.

[0128] Step 14, performing statistical analysis on the injury degree of the spinal cord obtained in step 12 to obtain the measured values ​​of the injury degree and volume as well as the percentage of retained tissue.

[0129] Specifically, measures of injury extent (length) and volume, as well as the percentage of preserved tissue, were analyzed using a mixed factorial method of variance (ANOVA) including the two factors day of injury and injury severity.

[0130] Further, where appropriate, Tukey-Kramer post hoc statistics were used to compare differences among groups, with significance set at p < 0.05.

[0131] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A device for making a spinal cord contusion model, characterized in that: The device comprises a fixture mounting platform, a striker mounting platform, an actuating transmission assembly, a striker and a vertebral fixture, forming a mobile bottom-free device for making a spinal cord contusion model; The striker mounting platform and the vertebral fixture are arranged on the fixture mounting platform; The actuating transmission assembly is arranged on the striking device mounting platform, the striking device is arranged on the actuating transmission assembly, and the actuating transmission assembly is used to drive the striking device; The vertebral clamp is used to clamp the vertebrae of the animal to be tested, and the impactor is used to impact the object to be tested to make a spinal cord contusion model; Determine the constraint conditions of the gravity component of the device used to make the spinal cord contusion model in the direction perpendicular to the device's equivalent lever for rotation; The deadweight of the device is determined based on the constraint conditions and the component of the gravity of the device in a direction perpendicular to the rotational equivalent lever of the device.

2. The device according to claim 1, characterized in that The fixture mounting platform is a fixture mounting bracket, which is used to adjust the three translational degrees of freedom of the striker mounting platform in the x, y and z axes.

3. The device according to claim 1, characterized in that The striker mounting platform is used to provide adjustment of the y-axis translational freedom for the actuating transmission assembly.

4. The device according to claim 3, characterized in that The actuating transmission assembly is used to provide the z-axis translation freedom adjustment for the driving striker.

5. The device according to claim 4, characterized in that The vertebral clamp is arranged on the clamp mounting platform so as to be translatable along the y-axis.

6. The device according to claim 1, characterized in that The fixture mounting platform includes an x-axis moving assembly, a y-axis moving assembly, and a z-axis moving assembly.

7. The device according to claim 6, characterized in that The expression for determining the constraint condition of the gravity component of the device used to make the spinal cord contusion model in the direction perpendicular to the equivalent lever of the device rotation is: Among them, F impact F represents the spinal cord contusion force applied by the impactor; mg is the component of the gravity of the device used to make the spinal cord contusion model in the direction perpendicular to the equivalent lever of the device rotation; H is the projection distance between the vertebral clamp and the bottom of the x-axis moving component on the y-axis; L is the distance between the vertebral clamp and the end of the x-axis moving component on the x-axis; ΔL is the projection distance between the vertebral clamp and the center line of the z-axis moving component on the x-axis.

8. The device according to claim 1, characterized in that The actuating transmission assembly includes a steering gear, a gear and a rack. The steering gear provides power, and the gear and rack transmit the power of the steering gear to the striker to drive the striker to move.

9. The device according to claim 1, characterized in that The striker comprises a striker tip and an x-axis translation freedom driving mechanism, wherein the x-axis translation freedom driving mechanism is used to give the striker tip an x-axis translation freedom.

10. A method for testing spinal cord contusion, characterized in that: The specific steps are: Using the device for making a spinal cord contusion model according to any one of claims 1 to 9 to make a spinal cord contusion on a test animal; The wound of the rat back with spinal cord contusion was sutured; The rats with back wound sutured were evaluated for ground hind limb movement within a set time to obtain the recovery of hind limb movement function after spinal cord injury. The injured spinal cord of rats was sampled and processed to obtain sections stained with chrome cyanine EC; The sections stained with chrome cyanine EC were subjected to histological analysis to obtain the extent of spinal cord injury and preserved tissue; The volume of injury and preserved tissue of the sections stained with chrome cyanine EC were obtained; Based on the extent of injury to the spinal cord, measurements of injury extent and volume as well as the percentage of preserved tissue are obtained.

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