An apparatus for making a spinal cord contusion model and a method for testing injury

Abstract

The present application relates to a kind of device for making spinal cord contusion model and damage test method, belong to spinal cord injury test field, solve the technical problems of the prior art instrument structure complex, bulky, high cost, and the consistency and repeatability of instrument making spinal cord contusion model is not high, simultaneously, the device for making spinal cord contusion model of the present application can move, also solve the problem that due to instrument fixation, need to transport rat in spinal cord injury experiment.The device for making spinal cord contusion model of the present application includes fixture installation platform, striker installation platform, actuating transmission assembly, striker and vertebral clamp;Form the device for making spinal cord contusion model of movable bottom plateless.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of spinal cord injury test, and particularly relates to a device for making a spinal cord contusion model and a test method, in particular to a device for making a spinal cord contusion model which is movable and has no bottom plate when making a spinal cord contusion model, and can avoid the transportation of rats during operation, firmly fix the vertebrae of rats, and accurately contuse the spinal cord of rats. BACKGROUND

[0002] In the research process of alleviating or curing traumatic spinal cord injury (SCI), the test device for spinal cord injury plays an important role. The existing test devices for spinal cord injury of rats can be roughly divided into two categories according to the different control variables of the injury degree: an instrument relying on force to control the injury degree and an instrument relying on displacement to control the injury degree. The perfect and most representative instruments are Infinite Horizon (IH impact system) and New York University (NYU impact system), as shown in FIG. 1. Among them, the IH impact system uses a sharp jaw similar to a tweezers (hereinafter referred to as IH clamp) to hold the vertebrae of rats, controls the impact force of the impactor by a microprocessor and a servo motor to injure the spinal cord, and returns the displacement or force parameters through a sensor; the NYU impact system uses a tooth clamp (hereinafter referred to as NYU clamp) to fix the vertebrae of rats, and then releases a weight of a certain mass from different heights to impact and contuse the spinal cord, and the impact speed is close to the terminal speed of the pure free-fall process corresponding to the height. Figure 6

[0003] When the above-mentioned instruments are used to perform spinal cord injury experiments, the vertebra clamp and the impactor are two important structures affecting the consistency and repeatability of the model, and the two instruments have limitations.

[0004] Firstly, the clamp: although the above-mentioned two impact systems can produce gradient spinal cord contusion with obvious score difference for rats, it can be observed from the pictures recorded by a high-speed camera that the clamp shakes obviously during the impact process. In addition, the clamps of IH and NYU have slight movement in the vertical direction, and the clamp shaking interferes with the experimental results. This clamp shaking phenomenon will affect the repeatability of the contusion model, so that the models of the same injury grade produce different substantial injuries and functional defects.

[0005] ​Secondly, the impactor: IH uses the pressure feedback by the impactor as the basis for determining whether the impactor continues to impact downward, which requires extremely sensitive and precise sensors and rapid feedback systems, and the device is high in requirements, complex in overall structure and high in cost; NYU directly releases a heavy object to impact the spinal cord, the impact time cannot be controlled, and the impactor bounces on the spinal cord, causing secondary bruising of the spinal cord.

[0006] In addition, the existing devices for making spinal cord injury models are all provided with fixed bases or need to be fixed on a table board. In the process of dissecting the back of a rat and exposing the spinal cord, a special sterile heating operating table provided with an anesthesia device is needed to ensure the anesthesia and survival of the rat during the operation. When the above-mentioned instrument is used to make a spinal cord injury, the rat that has completed the dissection and exposed the spinal cord needs to be transported in the operation, that is, transferred from the sterile heating operating table to the position below the spinal cord injury instrument. In this process, it is difficult to maintain the anesthesia supply of the rat, avoid spinal cord compression, and avoid wound bacterial contamination. SUMMARY

[0007] In view of the above problems, the present application provides a device for making a spinal cord contusion model and an experimental method, which solves the technical problems of the prior art that the instrument structure is complex, the size is large, the cost is high, and the consistency and repeatability of the instrument for making a spinal cord contusion model are not high. At the same time, the device for making a spinal cord contusion model of the present application can be moved, and the problem of transporting the rat in the spinal cord injury experiment caused by the fixed instrument is also solved.

[0008] The present application provides a device for making a spinal cord contusion model, comprising a clamp mounting platform, an impactor mounting platform, an actuating transmission assembly, an impactor and a vertebra clamp; forming a mobile bottomless device for making a spinal cord contusion model;

[0009] The impactor mounting platform and the vertebra clamp are arranged on the clamp mounting platform;

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

[0011] The vertebra clamp is used to clamp the vertebra of the animal to be tested, the impactor is used to give the animal to be tested an impact, and a spinal cord contusion model is made;

[0012] The constraint condition of the component force of the gravity of the device for making a spinal cord contusion model in the direction perpendicular to the equivalent lever of rotation of the device is determined;

[0013] The self-weight of the device is determined based on the constraint condition and the component force of the gravity of the device in the direction perpendicular to the equivalent lever of rotation of the device.

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

[0015] Optionally, the impactor mounting platform is used to adjust the translational degree of freedom of the actuating transmission assembly in the y axis.

[0016] Optionally, the actuating transmission assembly is used to adjust the translational degree of freedom of the driving impactor in the z axis.

[0017] Optionally, the vertebral clamp is arranged to be translatable in the y axis on the clamp mounting platform.

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

[0019] 7Optionally, the expression of the constraint condition of the component force of the gravity of the device for making a spinal cord contusion model in the direction perpendicular to the equivalent lever of the rotation of the device is as follows:

[0020]

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

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

[0023] Optionally, the impactor comprises an impactor tip and an x-axis translational degree of freedom driving mechanism, which is used to give the impactor tip an x-axis translational degree of freedom.

[0024] Another aspect of the present application also discloses a spinal cord contusion injury testing method, and the specific steps are as follows:

[0025] A spinal cord contusion is made on the animal to be tested using the device for making a spinal cord contusion model described above;

[0026] The back of the rat on which the spinal cord contusion is made is sutured;

[0027] The recovery of the movement function of the hind limbs of the rat after the spinal cord contusion is evaluated by ground hind limb movement evaluation of the rat after the back wound is sutured for a set time;

[0028] Sampling and processing the injured spinal cord of the rat to obtain the chrome cyanin EC staining section;

[0029] Histological analysis of the chrome cyanin EC staining section to obtain the injury degree and the reserved tissue of the spinal cord;

[0030] Obtaining the injury volume and the volume of the reserved tissue of the chrome cyanin EC staining section;

[0031] Based on the injury degree of the spinal cord, the measurement values of the injury degree and the volume and the percentage of the reserved tissue are obtained.

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

[0033] 1、The clamp mounting platform of the present application is a gantry structure with three degrees of freedom, and the precise positioning of the clamp in the experimental space can be conveniently realized through three groups of guide rails. At the same time, the fixed end beam structure composed of a pair of parallel screw guide rails and a cross beam can greatly improve the stability of the clamp and ensure that the clamp does not shake during the experiment of bruising the spinal cord.

[0034] 2、The striker mounting platform of the present application is installed on the cross beam of the clamp mounting platform, and can realize large-range displacement adjustment with the adjustment of the clamp mounting platform, thereby reducing the pressure of its own adjustment and positioning, and also improving the integration and use efficiency of the instrument.

[0035] 3、The present application is a movable structure as a whole, which can be removed or placed above the rat surgery platform at any time as needed. A pair of parallel screw guide rails with a specific weight are used at the bottom of the present application to serve as a support base, without the need for a bottom plate or a specially designed table top to fix and support. The stability of the instrument during use can be ensured through the self-weight of the three groups of guide rails and the rubber pad under the bottom guide rail, thereby improving the stability of the clamp.

[0036] 4、The striker of the present application uses a self-designed micro-precision slide rail group and a high-precision linear ball bearing as its internal support structure, which can provide adjustable degrees of freedom for the tip of the striker while ensuring that the tip of the striker remains stable enough during the impact of the spinal cord without bouncing and shaking. BRIEF DESCRIPTION OF DRAWINGS

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

[0038] Figure 2 It is a front view of the device for making a spinal cord contusion model of the present application containing a vertebral clamp;

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

[0040] Figure 4 Front view of the actuation transmission assembly of the device for making spinal cord contusion model of the present invention;

[0041] Figure 5 Front view of the striker of the device for making spinal cord contusion model of the present invention;

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

[0043] Figure 7 Side view of the device for making spinal cord contusion model of the present invention.

[0044] Reference signs:

[0045] 1-clamp mounting platform, 2-striker mounting platform, 3-actuation transmission assembly, 4-striker, 11-x-axis first guide rail base, 12-x-axis first guide rail slider, 13-x-axis hand crank, 14-cross beam, 15-z-axis movement synchronous wheel, 16-z-axis movement synchronous belt, 17-z-axis movement locking component, 18-first guide rail slider, 19-first guide rail base, 20-clamp mounting support, 21-vertebral clamp, 22-third guide rail crank, 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, 28-x-axis movement synchronous belt, 29-x-axis movement locking component, 30-x-axis movement synchronous wheel, 32-universal support rod, 33-cross rail connector, 34-rail, 35-actuation transmission assembly mounting support, 36-rudder, 37-gear, 38-rack, 39-second guide rail slider, 40-second guide rail base, 49-striker tip, 50-striker base, 51-micro slider, 52-cover plate, 53-high head knurled hand screw, 54-micro guide shaft, 55-M3 hexagonal nut, 56-micro ball bearing, 57-micro linear guide rail, 58-micro slider, 59-M3 hexagonal nut, 60-M3 hexagonal socket head cap screw, 61-M3 hexagonal nut, 62-high precision force sensor, 70-z-axis first guide rail base, 71-z-axis first guide rail slider, 72-z-axis second guide rail base, 73-z-axis second guide rail slider, 74-x-axis movement assembly end. DETAILED DESCRIPTION

[0046] To better understand the above-described objectives, features, and advantages of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other. Furthermore, the present invention can be implemented in other ways different from those described herein; therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0047] A specific embodiment of the present invention, such as Figures 1-6 A device for creating a spinal cord contusion model is disclosed, comprising a clamp mounting platform 1, an impactor mounting platform 2, an actuation transmission assembly 3, an impactor 4, a vertebral clamp 21, and a control system.

[0048] The vertebral clamp 21 and the impactor mounting platform 2 are mounted on the clamp mounting platform 1; the actuation transmission assembly and the impactor are mounted on the impactor mounting platform 2; a control box is also mounted on the clamp mounting platform 1 to control the movement of the impactor and receive measurement data from a high-precision force sensor.

[0049] Fixture mounting platform 1 is a fixture mounting bracket; impactor mounting platform 2 includes an impactor mounting bracket;

[0050] Preferably, the fixture mounting bracket is a gantry structure composed of three sets of lead screw guides, each responsible for adjusting the three translational degrees of freedom of the x, y, and z axes, enabling arbitrary positioning of the fixture in the operating space. The bottom set of lead screw guides has rubber pads attached to its base for anti-slip and shock absorption. In addition, the fixture mounting platform 1 also functions as a platform for mounting the impactor, improving instrument integration while reducing operational difficulty.

[0051] The impactor mounting platform 2 is used to mount the actuation transmission assembly 3 and the impactor 4. The impactor mounting platform 2 is mounted on the crossbeam 14 of the clamp mounting platform 1, allowing for a wide range of spatial position adjustments within the space. The impactor mounting platform 2 has a cross-shaped guide rail assembly composed of two lead screw guide rails arranged in a cross shape, providing translational freedom in both the y and z axes, thus offering two vertical adjustment functions for the impactor 4.

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

[0053] Among them, gear 37 is connected to servo motor 36 and then fixed together on actuation transmission component mounting bracket 35, rack 38 is fixed on striker base 50, and the servo motor and striker are transmitted through gear 37 and rack 38.

[0054] like Figure 5 The diagram shows the external shape of the striker 4 and its internal components. To prevent the striker tip 49 from wobbling or bouncing during impact, while also providing adjustable degrees of freedom for the striker tip 49, the striker 4 of the device for creating spinal cord contusion models of the present invention employs a self-designed miniature precision slide rail assembly and high-precision linear ball bearings as its internal support structure, which can ensure that the striker tip 49 maintains sufficient stability during the impact on the spinal cord. Specifically, the striker 4 includes a striker base 50, a slider 51, a cover plate 52, a striker tip 49, and high-head knurled hand-tightening bolts 53. An installation chamber is provided at the end of the striker base 50, and within the installation chamber are miniature guide shafts 54, miniature linear guides 57, miniature sliders 58, miniature ball bearings 56, M3 socket head cap screws 60, M3 hexagonal nuts 55, and M3 hexagonal nuts 59. The cover plate 52 is connected to the outside of the striker base 50 by 20mm long M3 socket head cap screws 60 and M3 hexagonal nuts 61. Two miniature guide shafts 54 are fixed between the striker base 50 and the cover plate 52. A miniature linear guide 57 and a pair of symmetrical M3 hexagonal nuts 59 are fixed on the miniature slider 58, allowing it to move along the miniature guide shafts 54. Sliding; the hand-tightening bolt 53 passes through a pair of miniature ball bearings 56 fixed at corresponding positions on 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 bearings 56, but can still rotate freely relative to other parts; the M3 hexagonal nut 59 on the miniature slider 58 engages 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, with an adjustable range of 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 along the miniature guide shaft 54 ​​with the miniature slider 58, and is given a translational degree of freedom in the x-axis.

[0055] like Figure 3 As shown, the cross-shaped guide rail assembly of the impactor mounting platform 2 and the miniature guide rail embedded in the impactor 4 together provide three translational degrees of freedom for the impactor tip 49, enabling the impactor tip 49 to be positioned arbitrarily within the operating space. The adjustable ranges in the x, y, and z directions are 10mm, 100mm, and 40mm, respectively.

[0056] Further, the clamp mounting platform 1 is designed as a gantry structure of a movable simply supported beam structure, comprising an x-axis moving assembly, a y-axis moving assembly and a z-axis moving assembly.

[0057] Preferably, the x-axis moving assembly comprises 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 x-axis first guide rail base 11 and the x-axis second guide rail base 25 each comprise a guide rail, a guide rail frame and a screw rod; the x-axis first guide rail slider 12 and the x-axis second guide rail slider 26 are respectively arranged on the screw rods of the x-axis first guide rail base 11 and the x-axis second guide rail base 25; the x-axis hand crank 13 is arranged at one end of the x-axis first guide rail base 11, and the x-axis moving locking component 29 is arranged at the same side end of the x-axis second guide rail base 25; the x-axis moving synchronous belt 28 connects the x-axis hand crank 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 13, the x-axis first guide rail slider 12 and the x-axis second guide rail slider 26 can move on the x-axis first guide rail base 11 and the x-axis second guide rail base 25, and the movable range is 200 mm.

[0059] Preferably, the z-axis moving assembly comprises 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 27, a z-axis moving synchronous belt 16 and a z-axis moving locking component 17.

[0060] The z-axis first guide rail base 70 and the z-axis second guide rail base 72 each comprise a guide rail, a guide rail frame and a screw rod; the z-axis first guide rail slider 71 and the z-axis second guide rail slider 73 are respectively arranged on the screw rods of the z-axis first guide rail base 70 and the z-axis second guide rail base 72; the z-axis hand crank 27 is arranged at one end of the z-axis first guide rail base 70, and the z-axis moving locking component 17 is arranged at the same side end of the z-axis second guide rail base 72; the z-axis moving synchronous belt 16 connects the guide rail hand crank 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 27, the z-axis first guide rail slider 71 and the z-axis second guide rail slider 73 can move on the z-axis first guide rail base 70 and the z-axis second guide rail base 72, and the movable range is 200 mm.

[0061] Preferably, the z-axis moving assembly comprises a cross beam 14, a third guide rail crank 22, a third guide rail slider 23 and a third guide rail base 24.

[0062] The crossbeam 14 is fixed to the first guide rail slider 71 and the second guide rail slider 73 along the z-axis, and is provided with double rows of guide grooves; the upper guide groove is used for the detachable installation of the first guide rail base 19 and the universal support rod 32 of the impactor mounting platform 2, and the lower guide groove is used to fix the third guide rail base 24; the third guide rail base 24 is provided with guide rails, guide rail frames and lead screws, and the third guide rail slider 23 is set on the lead screw of the third guide rail base 24, and can be adjusted and moved by the third guide rail handle 22, with a movable range of 100mm.

[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 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 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 subjected to an external force, the device is subjected to a clockwise direction ( Figure 7 The rotational torque M1 of the device is such that the device is equivalent to a linear lever connecting the vertebral clamp 21 and the bottom of the x-axis moving component, with the fixed fulcrum being the bottom of the x-axis moving component. This lever is called the device's rotational equivalent lever. Figure 7 (As shown by the thick dashed line in the side view of the device).

[0065] Determine the weight of the device used to create the spinal cord contusion model in the equivalent lever perpendicular to the device's rotation ( Figure 7 The component force F in the direction shown 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 Indicates the force applied by the impactor to injure the spinal cord; F mg Let G be the component of the gravity G of the device used to create a spinal cord contusion model in the direction perpendicular to the rotational equivalent lever of the device.

[0068] Specifically, F impact This indicates the spinal cord contusion force applied by the tip 49 of the striker.

[0069] Preferably, the force F that contuses the spinal cord impact Maximum not exceeding 50N.

[0070] Furthermore, the component of the gravity of the device used to create the spinal cord contusion model in the direction perpendicular to the equivalent lever direction of the device's rotation, F mg The expression is:

[0071]

[0072] Wherein, m is the self-weight of the device for making spinal cord contusion model, θ is the angle between the force F and the z axis, and g represents the acceleration of gravity. mg The force F is decomposed in the x-z axis plane mg The angle between the force F and the z axis; g represents the acceleration of gravity.

[0073] Further, based on the formulas (1) and (2), the self-weight m of the device for making spinal cord contusion model is obtained, and the expression is as follows:

[0074]

[0075] Preferably, m≥10kg.

[0076] Preferably, the constraint condition that the total weight m2 of the four sets of screw sliding rails of the x-axis moving assembly and the z-axis moving assembly and the self-weight m1 of the remaining components of the device for making spinal cord contusion model are determined, and the expression is as follows:

[0077] m=m1+m2;

[0078] m1g·ΔL<<m2g·L*(4)

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

[0080] Further, according to the constraint condition that the total weight m2 of the four sets of screw sliding rails of the x-axis moving assembly and the z-axis moving assembly and the self-weight m1 of the remaining components of the device for making spinal cord contusion model are determined, and the weight distribution of the total weight m2 of the four sets of screw sliding rails of the x-axis moving assembly and the z-axis moving assembly and the self-weight m1 of the remaining components of the device for making spinal cord contusion model is obtained.

[0081] Exemplarily, L*≈100mm, ΔL≈40mm,

[0082] At this time,

[0083] The constraint condition that the total weight m2 of the four sets of screw sliding rails of the x-axis moving assembly and the z-axis moving assembly and the self-weight m1 of the remaining components of the device for making spinal cord contusion model are determined is set

[0084]

[0085] Preferably, m2≥8Kg, m1≤2Kg.

[0086] Further, referring to the attached Figure 3The striker mounting platform 2 is mounted on the upper guide groove of the cross beam 14 of the z-axis moving assembly; the striker mounting platform 2 comprises a first guide rail sliding block 18, a first guide rail base 19, a second guide rail sliding block 39, a second guide rail base 40, a universal support rod 32, a cross guide rail connecting piece 33, a sliding 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 sliding block 18 is arranged on the first guide rail base 19 and can be adjusted to move within a range of 100 mm;

[0087] One side of the cross guide rail connecting piece 33 is arranged on the first guide rail sliding block 18, and the first guide rail sliding block 18 drives the cross guide rail connecting piece 33 to move along the y-axis; the other side of the cross guide rail connecting piece 33 is arranged on the second guide rail base 40, the second guide rail base 40 is provided with a guide rail and a screw rod, and the second guide rail sliding block 39 is slidingly arranged on the screw rod and can be adjusted to move within a range of 40 mm; one side of the actuating transmission assembly mounting bracket 35 is arranged on the second guide rail sliding block 39, and the second guide rail sliding block 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 with the sliding rail 34.

[0088] Further, referring to the accompanying drawings Figure 4 The actuating transmission assembly comprises a rudder 36, a gear 37 and a rack 38; the rudder 36 is connected with the gear 37, and the gear 37 is connected with the rack 38; the striker base 50 is arranged on the rack 38 and is slidingly connected with the sliding rail 34; the rudder 36 drives the gear 37 to rotate, the gear 37 drives the rack 38 to operate, and the rack 38 drives the striker base 50 to move along the z-axis direction. In the device, the rudder is of a single-shaft ZX20S type, which outputs torque through a single output shaft, can provide a maximum torque T=20 kg·cm, has a rotation accuracy of 0.24°, and has a maximum response speed ω=60° / 0.16s (375° / s); the gear has a modulus m=1, a number of teeth n=30, and a pitch circle diameter d1=m×n=30 mm; the rack also has a modulus of 1.

[0089] Further, the distance between the central axis of the striker tip 49 and the central axis of the output shaft of the rudder 36 is l, the size of l is adjusted by the high-head knurled hand screw bolt 53, and l∈[25, 35] mm; the maximum value of the force that can be output by the striker tip 49 is wherein T represents the maximum torque that can be provided by the rudder, 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 wherein ω represents the maximum angular velocity of the rudder response; d1 represents the pitch circle diameter.

[0091] The vertebral clamp 21 is arranged on the clamp mounting bracket 20, the clamp mounting bracket 20 is connected with the third guide rail sliding block 23, and the third guide rail sliding block 23 is on the lead screw of the third guide rail base 24.

[0092] The control system main chip is Atmel Mega328P, and five operation buttons are connected to control the operation of the steering gear 36; the five buttons each have different functions.

[0093] The key 1 and the key 2 are responsible for the 'preset' and 'zero' functions of the striker, wherein the 'preset' function is that the steering gear 36 rotates clockwise, so that the striker tip 49 reaches a specific position close to the spinal cord, and the position is controlled by the parameter setting in the program; the 'zero' function is opposite to the 'preset' function, and the steering gear 36 is controlled to rotate counterclockwise, so that the striker tip 49 reaches the position farthest from the spinal cord. During the braking process of the steering gear, when the speed is large, overtravel phenomenon usually occurs, that is, the steering gear rotates beyond the preset position and then reverses to adjust to the preset position; in the above one-way displacement process of 'preset' and 'zero', in order to avoid the interference of overtravel displacement on the experiment, two-stage displacement control is adopted, in the first stage control, the steering gear 36 rotates to move the striker tip 49 to a position 1mm away from the target position, and then the second stage control is immediately started to continue moving the striker tip 49 by 1mm, so that the striker tip 49 can finally accurately move to the target position, avoiding the interference of overtravel phenomenon on the experiment.

[0094] The key 3 and the key 4 are responsible for regulating and controlling the striking depth x, x∈[0.5, 2.5]mm, the key 3 is pressed to increase x, and the key 4 is pressed to decrease x, and each adjustment increases / decreases by 0.1mm, and this function provides more selectable damage gradients and more accurate damage control for the user;

[0095] The key 5 controls the'striking' function of the striker, after the setting of the striking depth and the positioning of the striker tip 49, the key 5 is pressed to start the'striking' process. In order to make the striker tip 49 have a higher instantaneous damage speed in the process of bruising the spinal cord, the'striking' process innovatively adopts a three-stage design, in the order of lifting, bruising and resetting. In the lifting stage, the steering gear 36 rotates counterclockwise to lift the striker tip 49 by 10mm; in the bruising stage, the steering gear 36 rotates clockwise to move the striker tip 49 downward by (10+x)mm, causing a damage of xmm in depth to the spinal cord; in the resetting stage, in order to prevent the striker tip from staying and causing secondary damage to the spinal cord, after the bruising is completed, the steering gear 36 quickly rotates counterclockwise to lift the striker tip 49 to a position 20mm away from the spinal cord.

[0096] The device adopts a high-precision steering gear as a driving component, and converts the rotation process into a linear motion process through a gear and rack set. In this process, the rotation angle of the steering gear 36 is The striking depth x of the striker tip 49 has a linear mapping relationship, and the function relationship expression is That is, by operating the steering gear 36 to rotate by a corresponding angle That is, the striker tip 49 can be moved by a preset striking depth x.

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

[0098] In addition, the control system of the device reserves an additional steering gear interface and an A4988 chip socket, and other functions can be expanded in the future.

[0099] Further, another embodiment of the application is also disclosed, which uses a 42-step motor or a 57-step motor to drive the rotation of the lead screw, connects the motor output shaft to the guide rail lead screw through a shaft coupling, and then controls the motor operation through an A4988 chip to complete the adjustment of the spatial position of the guide rail.

[0100] Further, another embodiment of the application is also disclosed, which uses a more expensive and more precise servo motor as a driving component to achieve higher precision and faster speed.

[0101] Further, another embodiment of the application is also disclosed, which uses a 1-module 30-tooth gear 37 and a 1-module rack 38 as transmission components to enable the impact speed of the striker tip to reach about 100mm / s. The improved scheme can replace the gear and rack set with different teeth to change the impact speed of the striker tip; for example, the gear teeth are reduced, and when the gear module m is 1 and the number of teeth n2 is 20, the pitch diameter of the gear is d2=m*n=20mm, and the maximum running speed of the striker tip 49 is

[0102]

[0103] In another aspect of the application, an experimental method for spinal cord contusion is provided, which uses the device for making a spinal cord contusion model to make a spinal cord contusion, and the specific steps are as follows:

[0104] During the experiment using the device, the clamp mounting platform is used for supporting and positioning the vertebral clamp, the vertebral clamp 21 is used for fixing the vertebra, the striker mounting platform is used for supporting and positioning the striker and the actuating transmission assembly, the striker tip 49 is used for contusing the spinal cord, and the actuating transmission assembly is used for providing power to the striker.

[0105] In addition, the experimental process also involves the use of a rat stereotaxic instrument and other surgical instruments, wherein the rat stereotaxic instrument is a rat dissection operating table.

[0106] In particular, during the course of the present experiment also included the use of a high-speed video camera, which was aligned parallel to the stereotaxic apparatus of the rat, placed on a tripod at a distance of 50 cm, when the spinal cord was injured. The high-speed video camera had a full-frame (10 million pixels) shooting rate of > 12600 frames / s; a maximum shooting rate of no less than 550000 frames / s, a sensitivity of 100000 black and white, and a high-speed cache DRAM of > 72 GB. The high-speed video camera captured dynamic images of the changes in the spinal cord at the moment of injury, and the video recording was played back by an observer frame by frame in order to observe the relative movement between the vertebral clamp 21, the clamp mounting bracket 20, and the tip of the striker 49 within the field of view during the injury process.

[0107] Step S1, select suitable individuals of rats for making spinal cord contusion model, the same group of individuals should ensure the same gender, similar weight, similar size, usually select 300g male rats as experimental individuals.

[0108] Step S2, anesthetize the experimental individual with chloral hydrate, place it on the stereotaxic apparatus of the rat, and fix the rat's head with a mask and ear bar; use a hair clipper to remove the fur on the back and around the T8-T11 vertebrae, complete the skin preparation operation; dissect the rat to expose the T8-T11 segment vertebrae of the rat, remove the T9 vertebral lamina and T8 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 a surgical microscope can be used to observe the position of the clamp to ensure that the clamp is tightly clamped; use a torque screwdriver to tighten the clamp to 2.7 N / cm during the screw tightening process to ensure consistent grip and prevent over-tightening;

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

[0111] Step S5, the device is transferred to the top of the rat stereotaxic instrument, the x-axis first guide rail base 11 and the x-axis second guide rail base 25 are placed on both sides of the rat stereotaxic instrument, at this time the rat head is towards the x-axis hand crank 13; the x-axis hand crank 13 and the z-axis hand crank 27 are adjusted, the clamp mounting bracket 20 is close to the vertebral clamp 21 on the x, z axis; the small guide rail crank 22 is adjusted, the third guide rail slider 23 moves along the third guide rail base 24, the clamp mounting bracket 20 is close to the vertebral clamp 21 on the y axis; the fixed bolt between the mounting holes is tightened by using the torque screwdriver, the vertebral clamp 21 is fixed to the clamp mounting bracket 20; the x-axis movement locking part 29 and the z-axis movement locking part 17 are locked, the position of each guide rail slider is locked, and thus the vertebral fixation of the experimental site of the rat is completed.

[0112] Step S6, the first guide rail slider 18 in the impactor mounting platform 2 is adjusted by the small guide rail crank, the micro slider 58 is adjusted by the high head knurled hand screw 53, the impactor tip 49 is opposite to the exposed spinal cord on the x, y axis (in the overhead state), the impactor tip 49 reaches the preset position by using the control system button 1, the second guide rail slider 39 is positioned by rotating the small guide rail crank of the second guide rail, and the lower end of the impactor tip 49 is lowered to just contact the surface of the exposed spinal cord; thus the positioning work of the impactor tip 49 is completed. The data acquisition card of the high-precision force sensor 62 is wirelessly connected to the computer, the data acquisition system is opened, and the force parameters of the impactor tip during the process of bruising the spinal cord are prepared to be collected.

[0113] Step S7, according to the experimental requirements, the impact depth x is set by using the button 3 and the button 4 of the control system, wherein x∈[0.5, 2.5] mm; the button 5 is pressed, and the "impact" process is completed; in this process, the dynamic images of the spinal cord changes at the moment of causing the spinal cord injury are captured by the high-speed camera, the video record is played frame by frame by the observer, so as to observe the relative movement between the vertebral clamp 21, the clamp mounting bracket 20 and the impactor tip 49 in the field of view during the injury process, and the effectiveness thereof is quantitatively evaluated. After the end of this process, the impactor tip 49 stays 20 mm away from the surface of the spinal cord;

[0114] Step S8, the impactor tip 49 is away from the spinal cord to the "zero" position by using the button 2, and the connection between the vertebral clamp 21 and the clamp mounting bracket 20 is released; the x-axis hand crank 13 and the z-axis hand crank 27 are adjusted, and the clamp mounting bracket 20 is away from the vertebral clamp 21; the device is moved away from the rat stereotaxic instrument, the wound on the back of the rat is sutured after removing the vertebral clamp 21, and the experiment is completed.

[0115] Step S9, store the collected force parameter data during the experiment, import into MATLAB, remove the useless data at the head and tail of the data set, draw the force image of the striking process, and find the maximum value of the force in the bruising process through the max function. Correspond the striking displacement to the maximum force value one by one, calculate the variance S of the maximum force value under the same striking displacement, and use it to calculate the repeatability of the device.

[0116] Step S10, continuously evaluate the ground hindlimb movement of the injured rat within 2 months after the back wound is sutured, and obtain the recovery of the hindlimb movement function of the rat after spinal cord injury.

[0117] Specifically, the Basso, Beattie, Bresnahan movement score scale (BBB score) is used to score the movement recovery of the experimental rats on the 7th, 14th, 21st, 28th, 35th, 42nd, 49th and 56th day after the back wound of the rat is sutured, and a BBB score-time t function is drawn. Variance analysis is used to study the differences between the spinal cord injury rats with different injury degrees or different postoperative treatments. The significance standard of the difference between different experimental groups is 0.05. When the significance level p<0.05, it is considered that there is a difference between groups.

[0118] Step S11, sample and process the damaged spinal cord of the rat to obtain the EC-stained section.

[0119] Specifically, the rat is injected with an overdose of sodium pentobarbital for anesthesia, and then heart perfusion is performed with 0.1M phosphate buffer (PBS, pH 7.4), followed by perfusion with PBS mixed with 4% paraformaldehyde (PF).

[0120] Further, in order to maintain the consistency of sampling, each spinal cord is transected at the thoracic vertebra T6 segment spinal cord nerve root of the sampled sample, a 3cm long spinal cord segment is dissected backward, and fixed in 4℃ paraformaldehyde PF for 2 hours, and then placed in 4℃ 20% sucrose / PBS for cryoprotection. The spinal cord is continuously frozen sectioned to 20 microns and mounted on gelatin-coated slides. EC is a dye that can bind to specific components in tissues. In spinal cord tissue, it can stain structures such as myelin sheath, thereby distinguishing white matter and cell bodies. White matter mainly contains nerve fibers and myelin sheath, and after staining, the range and morphology of white matter can be clearly shown; for the cell body part, staining can help to observe the condition of neuron cell bodies, such as their number change, morphological change, etc. after spinal cord injury. The obtained spinal cord section is stained using the EC staining scheme to obtain the EC-stained section, so as to calculate the number of retained tissues in the transverse section of the injured spinal cord in the subsequent calculation; wherein the retained tissue refers to the tissue that is positive for myelin sheath staining or has cell structure similar to that of the control group section, i.e. it is considered to be a normal functional tissue.

[0121] Step 12, histological analysis of EC-stained sections was performed to determine the center of spinal cord injury and to preliminarily obtain the injury degree of the spinal cord.

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

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

[0124] It can be understood that the tissue of the lesion center of each spinal cord is the section with the largest percentage of lesion tissue to total stained tissue.

[0125] Step 13, the injury volume and the volume of the preserved tissue of the EC-stained sections were obtained.

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

[0127] Further, when calculating the preservation of the tissue at the injury site, a cross-sectional area correction factor (CF) obtained from the intact distal spinal cord tissue was considered to avoid the problem of being difficult to accurately measure the pre-injury volume required for tissue preservation caused by tissue contraction due to injury.

[0128] Step 14, statistical analysis of the injury degree of the spinal cord obtained in step 12 was performed to obtain the measurement values of the injury degree and volume and the percentage of the preserved tissue.

[0129] Specifically, the measurement values of the injury degree (length) and volume and the percentage of the preserved tissue were analyzed using a mixed factor variance method (ANOVA) containing two factors of injury days and injury severity.

[0130] Further, in appropriate cases, Tukey-Kramer post hoc statistics was used to compare the differences between groups, and the significance was set as p<0.05.

[0131] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A device for creating a spinal cord contusion model, characterized in that, Includes a clamp mounting platform, an impactor mounting platform, an actuation transmission assembly, an impactor, and a vertebral clamp; forming a movable, bottomless device for creating a spinal cord contusion model; The impactor mounting platform and the vertebral clamp are mounted on the clamp mounting platform; The actuation transmission assembly is mounted on the striker mounting platform, the striker is mounted on the actuation transmission assembly, and the actuation transmission assembly is used to drive the striker. Vertebral clamps are used to hold the vertebrae of the animal to be tested, and impactors are used to strike the animal to create a spinal cord contusion model. The fixture mounting platform includes an x-axis moving assembly, a y-axis moving assembly, and a z-axis moving assembly; The constraint condition for the component of gravity of the device used to create the spinal cord contusion model in the direction perpendicular to the rotational equivalent lever of the device is determined by the following expression: in, This indicates the force applied by the striking device to injure the spinal cord; Let H be the component of the gravity of the device used to create a spinal cord contusion model in the direction perpendicular to the equivalent lever of the device's rotation; H represents the projected distance between the vertebral clamp and the bottom of the x-axis moving component on the y-axis; L represents the distance between the vertebral clamp and the end of the x-axis moving component on the x-axis. This represents the projected distance on the x-axis between the centerline of the vertebral clamp and the z-axis moving component; The self-weight of the device is determined based on the constraints and the component of the device's gravity in the direction perpendicular to the equivalent lever direction of the device's rotation, expressed as: Where g represents gravitational acceleration.

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

3. The apparatus according to claim 1, characterized in that, The impactor mounting platform is used to adjust the y-axis translational degree of freedom of the actuation transmission assembly.

4. The apparatus according to claim 3, characterized in that, The actuation transmission assembly is used to adjust the z-axis translational degree of freedom of the drive impactor.

5. The apparatus according to claim 4, characterized in that, The vertebral clamp is translatably mounted on the clamp mounting platform along the y-axis.

6. The apparatus according to claim 1, characterized in that, The actuation transmission assembly includes a servo motor, gears, and a rack. The servo motor provides power, and the gears and rack transmit the power of the servo motor to the striker to drive the striker to move.

7. The apparatus according to claim 1, characterized in that, The striker includes a striker tip and an x-axis translational degree-of-freedom drive mechanism, which is used to give the striker tip x-axis translational degree of freedom.

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