Construction method of mouse model for rapid maxillary expansion

Abstract

The invention discloses a construction method of a mouse model for rapid maxillary expansion. The construction method comprises the steps of installation of the mouse model and installation of an expansion device. The mouse model installation method comprises the following steps: (1) anesthesia; (2) fixing on an experiment table, and exposing the palate part of the upper jaw to a molar area; (3) pretreating the lip surface of the maxillary incisor; the installation method of the extension device comprises the following steps: (1) cutting out four ligature wires, namely A and B; fixing the section A ligature wire at a retention groove at the neck part of the incisors on one side; (2) cutting a nickel-titanium wire, and bending the nickel-titanium wire into a teardrop shape; and (3) respectively fixing the free end parts on the two sides of the nickel-titanium wire at the distal positions of the two maxillary incisor teeth by using the two B-section ligature wires, wherein the nickel-titanium wire is integrally close to the palate part of the mouse. Through the reasonable design and installation method, the stability of the model is improved, the stress application accuracy and consistency in the experiment process are ensured, and a better mechanical model is provided for cell biology and morphology research.

Description

Technical Field

[0001] The present invention relates to the field of oral orthodontic mechanics research, in particular to the establishment and application of a mouse rapid maxillary expansion (RME) model, and belongs to animal experimental model technology. Background Art

[0002] Rapid midpalatal expansion (RME) is a commonly used orthodontic treatment method aimed at correcting the lack of transverse development of the maxilla. This technique promotes the separation of the midpalatal suture bones and increases the width of the maxillary arch by applying rapid, high-intensity mechanical expansion forces. The effectiveness of RME relies on the biological process of bone formation and bone resorption: when the expansion force is applied, the mechanical stress stimulates the periosteum and endosteum, leading to the proliferation of osteoblasts and new bone deposition; at the same time, osteoclasts absorb the bone at the edge of the expansion gap to ensure the balanced integration of the new bone.

[0003] Currently, animal models for studying the mechanism of RME mainly include mice, rats, and rabbits. These models have certain similarities in simulating the process of maxillary gap expansion in humans and can provide valuable data on bone remodeling and cellular responses.

[0004] However, the patent applicant found that the existing expansion device and modeling method for mouse modeling are basically copied from the expansion device and modeling method for rats, but due to the great differences between the internal structure and force of the oral cavity of mice and rats, many inapplicability problems arise, such as easy to fall off, low efficiency, affecting the normal feeding of mice, requiring special feeding and complicated operation, which in turn affects the repeatability and stability of the experiment.

[0005] Among them, the so-called rats, taking SD rats as an example, the weight of male rats at 10 weeks of age can reach 300-400g, the average curvature radius of the upper incisor is (7.01±0.42) mm, and the tooth length is (25.04±1.88) mm. Taking C57BL / 6 mice used in this experiment as an example, the weight of male rats at 6-8 weeks of age can reach 20-25g, the average curvature radius of the upper incisor is (2.37±0.11) mm, and the tooth length is (8.63±0.63) mm.

[0006] The patent applicant retrieved a patent on rat modeling method - CN112972049B, a method for constructing an animal model of SD rats for rapid maxillary expansion, wherein the expander is made of stainless steel wire, the middle of which is bent into a ring curve 1 with a diameter of 2mm, and the long arms 2 on both sides are bent in opposite directions to form a symmetrical structure, and a bend is added at 2mm of the long arm, and the minimum angle between the bend and the horizontal direction is 45-60°; the tail ends of the long arms on both sides are bent outward to form a hook-shaped structure. The ring curve is bonded to the bends of the long arms on both sides with light-curing resin. The requirements for placing the expander between the maxillary incisors are: the side of the long arms on both sides that is horizontal to the ring curve faces downward, as close to the palatal mucosa as possible; the ring curve just surrounds the palatal papilla; the tail ends of the long arms are clamped on the mesial surface of the incisors on both sides and extend to the buccal side, without tilting in the horizontal or vertical direction. The above-mentioned prior patents also reveal the disadvantages of transferring the rat modeling method to mouse modeling, including the following two points.

[0007] First, the tail section of the expander of the prior patent obviously protrudes from the labial surface of the rat incisor (the buccal side of the prior patent is the labial surface of the present patent application), which makes the mouse feel obviously uncomfortable when used in the oral cavity, especially when it is chewing food, which makes it necessary to feed the mouse in a special way, that is, the food needs to be mashed into a paste and fed to the mouse. However, even with special feeding, since the expander obviously protrudes from the labial surface of the incisor, it will often fall off during the mouse's oral activities, thus affecting the experimental efficiency, and further affecting the repeatability and stability of the experiment.

[0008] Secondly, the expander of the prior patent is made of stainless steel wire, with a ring curve in the middle and two long arms set between the two incisors. The ring curve provides a restoring force when deformed by force to open the two long arms and provide expansion force. It can be seen that the elastic force of the ring curve is mainly used in this process, and the two stainless steel wire long arms are almost only used to transmit the elastic force of the ring curve. Therefore, the expansion force of the expander is relatively rigid. When used in mice, the expansion force is too strong and the expansion effect is not ideal.

[0009] It can be seen that this type of rat modeling method is not suitable for mouse modeling because of the expansion force value and the size of the expansion device. Due to its particularity, mice still do not have a very suitable expansion device and modeling method. Summary of the invention

[0010] In order to solve the above problems existing in the prior art, the purpose of the present invention is to provide a method for constructing a mouse model of rapid maxillary expansion, which is not easy to fall off, does not require special feeding, is simple to operate, has high efficiency, and has excellent experimental repeatability and stability.

[0011] The technical solution adopted by the present invention to solve the technical problem is: a method for constructing a mouse model for rapid maxillary expansion, the steps of which include installing the mouse model and installing an expansion device;

[0012] The steps of installing the mouse model are as follows:

[0013] (1) Anesthetizing mice;

[0014] (2) The anesthetized mouse was fixed on the experimental table in a supine position, the head was raised, and the mouth was opened to expose the maxillary palate to the molar area;

[0015] (3) pre-treating the maxillary incisor of the mouse, and making a retention groove on the mesiogingival distal side of the maxillary incisor using an electric carving knife;

[0016] The steps of installing the expansion device are as follows:

[0017] (1) Four ligatures with a diameter of 0.08 mm were cut and named as segments A and B, two each. One of the ligatures of segment A was passed through the gap between the two maxillary incisors and fixed at the retention groove of the neck of the incisor on one side. The same operation was performed on the maxillary incisor on the other side.

[0018] (2) a section of nickel-titanium wire with a diameter of 0.15 mm was cut and bent into a teardrop shape with a distance of 1.4 cm from the bottom of the bend to the free end using a needle holder;

[0019] (3) using the two sections of the B-section ligature wires to respectively ligate and fix the free ends of the nickel-titanium wire on the two sections of the A-section ligature wires, thereby respectively fixing the free ends of the nickel-titanium wire on the distal positions of the two maxillary incisors, so that the nickel-titanium wire forms a U-shape, and the nickel-titanium wire is close to the palate of the mouse and firmly fixed in its oral cavity;

[0020] (4) A thin layer of fluid resin is applied to the free end of the nickel-titanium wire, the A-section ligature wire, the B-section ligature wire and the distal side of the maxillary incisor, and light-cured after trimming with a probe. The surface is polished with a grinder, and the free end of the nickel-titanium wire is trimmed so that the free end does not protrude outside the cured resin. At the same time, ensure that the distance from the bottom of the curve to the cutting edge of the maxillary incisor is 1 cm.

[0021] Compared with the existing technology, it has the following positive effects:

[0022] 1. The expansion device of the present invention uses the ligature wire of section A and the ligature wire of section B to fix the free ends of the nickel-titanium wire on both sides at the distal position of the two maxillary incisors, respectively, so that there is no need to grind the suture between the two maxillary incisors of the mouse. It should be noted that the teeth of mice are extremely small, and grinding the suture is not only extremely difficult, but also easy to cause the teeth of mice to collapse. Existing devices are mostly suitable for rats, and the weight difference between rats and mice is as much as 10 times. The size and force of the rat expansion device are not suitable for mice. The expansion device of the present invention uses a softer force and a more delicate ligature fixation method to open the mouse's jaw suture.

[0023] 2. The expansion device of the present invention utilizes a ligature wire with a small diameter to ligate a U-shaped wire with a large diameter. This arrangement not only has a stable structure, but also does not cause obvious protrusions on the labial surface of the maxillary incisor. Although the prior patent did not disclose the diameter of the stainless steel wire used, its background technology mentioned that the diameter of the prior art expansion and retention device is 0.014 inches (about 0.356 mm), while the ligature wire for ligating the A section of the maxillary incisor of the present invention is only 0.08 mm, and the force arch wire is only 0.15 mm, and all are placed in the distal groove of the incisor and sealed with resin, so there will be no obvious protrusions on the labial surface of the maxillary incisor. It can be seen that the expansion device of the present invention will not affect the normal feeding of mice, and no special feeding is required.

[0024] 3. The present invention makes a retention groove on the distal side of the mesigma side of the maxillary incisor of the mouse, so that the A-section ligature wire is embedded in the retention groove, so that the A-section ligature wire is not easy to fall off, thereby improving the efficiency of the experiment, and further improving the repeatability and stability of the experiment.

[0025] 4. The present invention uses U-shaped nickel-titanium wire, as opposed to the stainless steel wire with annular bends used in prior patents. First, the U-shaped nickel-titanium wire utilizes the resilience of the memory metal properties of the nickel-titanium wire, and the entire section of nickel-titanium wire implements a gentle expansion force, rather than the relatively rigid elastic force of the annular bend as in prior patents. Secondly, the U-shaped nickel-titanium wire of the present invention utilizes the resilience of the memory metal properties, and there is no need to make annular bends, thereby avoiding thickness superposition, making the U-shaped nickel-titanium wire fit more closely to the mouse's upper jaw. It should be emphasized that the material and size of the U-shaped nickel-titanium wire of the present invention are obtained by the patent applicant after multiple material and size tests, which is the result of huge creative labor and is not borrowed from prior art.

[0026] 5. The ligation site of the expansion device of the present invention is coated with resin, so that the ligation site is firm and not easy to be removed, and the foreign body sensation of the mice is reduced, further ensuring that the normal feeding of the mice is not affected, reducing the difficulty of feeding, and improving the repeatability and stability of the experiment.

[0027] 6. Since the expansion force of the expansion device is affected by the distance from the curved bottom of the nickel-titanium wire to the incisor edge of the maxillary incisor, the patent applicant has confirmed through multiple experiments that the most efficient expansion force is when the distance from the curved bottom of the nickel-titanium wire to the incisor edge of the maxillary incisor is 1 cm, and ensures that the expansion force applied during the experiment remains consistent.

[0028] 7. The modeling method of the present invention improves the stability of the model through reasonable design and installation methods, ensures the accuracy and consistency of force application during the experiment, and provides a better mechanical model for cell biology and morphology research.

[0029] Specifically, the step (1) of installing the mouse model is to weigh the mouse and then perform anesthesia by intraperitoneal injection of 0.4% sodium pentobarbital at a dose of 0.12 mL / 10 g, and the disappearance of conjunctival reflex is used as a sign of successful anesthesia.

[0030] Specifically, the depth of the retention groove in step (3) of installing the mouse model is 0.5 mm, and the diameter of the ligature wire of segment A is 0.08 mm, so that the ligature wire of segment A is well ligated on the retention groove and does not fall off.

[0031] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the present invention using an expansion device to expand the upper jaw of a mouse.

[0033] Figure 2 This is a photograph of a mouse subjected to the method for constructing a mouse model of rapid maxillary expansion of the present invention.

[0034] Figure 3 is the body weight of the mice in the experiment.

[0035] Figure 4 is the distance between the front, middle and back seams of MicroCT.

[0036] Figure 5 It is the data analysis of MicroCT posterior suture.

[0037] Figure 6 This is the result of HE staining of the section (anterior, middle and posterior seams).

[0038] Figure 7 The figure shows the shedding rate of expansion devices using U-shaped nickel-titanium wires of different diameters in the mouse arch expansion experiment.

[0039] Figure 8 It is the force measurement of the expansion device with U-shaped nickel-titanium wire and a diameter of 0.3mm.

[0040] Fig. 9It is the force measurement of the expansion device with U-shaped nickel-titanium wire and a diameter of 0.15mm.

[0041] Among them, maxillary incisor-10; segment A ligature wire-22; segment B ligature wire-24; nickel-titanium wire-30; free end-31; curved bottom-33. DETAILED DESCRIPTION

[0042] The technical scheme and advantages of the present invention are further described in detail below in conjunction with the accompanying drawings. The description herein is only used to explain the design of the present invention and is not intended to limit the present invention. It should be emphasized that the following detailed descriptions are all exemplary, and the description of the modeling method and characteristics of the rapid expansion of the mid-palatal suture in mice should not constitute any limitation on the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as those commonly understood by ordinary technicians in the technical field to which this patent application belongs.

[0043] It should be noted that the related terms labial side, lingual side, mesial side and distal side are industry terms for orthodontic treatment. Taking the maxillary teeth as an example, the surface facing the lips is the labial surface of the tooth, and the labial side is the labial side; the surface facing the tongue is the lingual surface of the tooth, and the lingual side is the lingual side; the labial surface and the lingual surface are opposite, and the direction formed by the labial side and the lingual side is also called the labial-lingual direction. The surface facing the mandibular teeth is the occlusal surface of the tooth; the surface connected to the gingival tissue is the gingival surface of the tooth; the occlusal surface and the gingival surface are opposite, and the direction formed by the occlusal surface and the gingival surface is also called the gingival direction. The left and right sides of the tooth are the mesial side and the distal side of the tooth, respectively. The so-called mesial refers to the side close to the incisor (commonly known as the front teeth), and the so-called distal refers to the side away from the incisor and close to the molar. The direction formed by the mesial side and the distal side is also called the mesiodistal direction.

[0044] Among them, the buccal side in the prior patent refers to the cheek side, which is the same as the lip side in this patent application.

[0045] like Figure 1 and Figure 2 As shown, the method for constructing a mouse model for rapid maxillary expansion in this embodiment includes the steps of installing the mouse model and installing the expansion device.

[0046] The steps for installing the mouse model are as follows:

[0047] (1) After weighing, 0.4% sodium pentobarbital was injected intraperitoneally at a dose of 0.12 mL / 10 g. The disappearance of conjunctival reflex was regarded as a sign of successful anesthesia.

[0048] (2) The anesthetized mouse was fixed in supine position on the experimental table, the head was raised, and the mouth of the mouse was fixed with an opener so that the mouth was opened to expose the maxillary palate to the molar area;

[0049] (3) The maxillary incisor 10 of the mouse was pretreated, and a retention groove with a depth of about 0.5 mm was made on the mesiogingival distal side of the maxillary incisor 10 using an electric carving knife.

[0050] The design and installation steps of the expansion device are as follows:

[0051] (1) Cut four ligature wires with a diameter of 0.08 mm and name them as Section A and Section B, two each; pass one of the ligature wires 22 of Section A through the gap between the bilateral incisors and fix it in the retention groove of the neck of one incisor; do the same with the other incisor;

[0052] (2) a section of nickel-titanium wire 30 with a diameter of 0.15 mm is cut, the free end 31 thereof is clamped with a needle holder, and the wire is bent into a teardrop shape with a distance of 1.4 cm from the bent bottom 33 to the free end 31;

[0053] (3) Using the B-section ligature wire 24, the free ends 31 on both sides of the nickel-titanium wire 30 are ligated and fixed at the distal position of the maxillary incisor 10, so that it forms a "U-shape", close to the palate and firmly fixed in the oral cavity of the mouse; specifically, using two sections of B-section ligature wires 24 to ligate and fix the free ends 31 on both sides of the nickel-titanium wire 30 on the two sections of A-section ligature wires 22, so that the free ends 31 on both sides of the nickel-titanium wire 30 are respectively fixed at the distal position of the two maxillary incisors 10, so that the nickel-titanium wire 30 forms a U-shape, close to the palate of the mouse and firmly fixed in its oral cavity.

[0054] (4) A thin layer of fluid resin was applied to the free end 31 of the nickel-titanium wire, the A-segment ligature wire 22, the B-segment ligature wire 24, and the distal side of the maxillary incisor 10. The wire was trimmed with a probe and then light-cured. The surface was polished with a grinder. The free end 31 of the nickel-titanium wire 30 was trimmed so that the free end 31 did not protrude from the cured resin. At the same time, the distance from the bent bottom 33 to the cutting edge of the maxillary incisor 10 was 1 cm, so that the force was gentle and easy to operate under the space limitation of the mouse's oral cavity.

[0055] Compared with the prior art, the method for constructing a mouse model of rapid maxillary expansion in this embodiment establishes a more efficient and stable mouse palatal suture rapid expansion model to improve the existing model's defects such as falling off, instability of force application, affecting normal feeding of mice, and difficulty in operation during the experiment. The present invention improves the stability of the model through reasonable design and installation methods, ensures the accuracy and consistency of force application during the experiment, and provides a better mechanical model for cell biology and morphology research.

[0056] Figure 3 is the body weight of mice in the above experiments. Figure 4-Figure 6 is the data obtained from the above experiment. Among them, Figure 4It can be seen that within 7 days, the expansion distances of the anterior, middle and posterior sutures increased significantly, all of which were statistically significant. Figure 5 The microCT measurement results are shown. The posterior suture volume, bone mineral density (BMD), bone volume (BV), trabecular number (Tb.N), trabecular separation (Tb.Th), and trabecular thickness (Tb.Sp) measured values ​​increased to varying degrees after 7 days, indicating that both osteoclastogenesis and osteolysis were ongoing, effectively opening the mid-jaw suture. Figure 6 The HE staining of the mid-Jia suture section shows the stable expansion process of the anterior, middle and posterior sutures.

[0057] The material and size of the U-shaped nickel-titanium wire of the present invention are obtained by the patent applicant after multiple material and size tests, which is a huge creative effort and not borrowed from the prior art. Specifically, it is obtained through the following tests.

[0058] like Figure 7 As shown in Figure 2, different diameters of nickel-titanium wires were used for arch expansion, resulting in different device detachment rates. Figure 7 It can be seen that the shedding rate of the U-shaped nickel-titanium wire with a diameter of 0.5 mm is the highest, and the shedding rate is almost 100% in 2 days. When the size of the arch wire is further reduced, when the diameter of the U-shaped nickel-titanium wire is 0.3 mm, the shedding rate is significantly improved. When the diameter of the U-shaped nickel-titanium wire is 0.15 mm, the shedding rate is almost 0%, reaching the best state. However, when the size of the arch wire is further reduced, the size of the arch wire cannot be further reduced to less than 0.15 mm because the arch wire is too thin and loses its expansion force and the operation is difficult.

[0059] Excluding the case where the U-shaped nickel-titanium wire diameter is 0.5 mm, the force values ​​of the expansion devices with U-shaped nickel-titanium wire diameters of 0.3 mm and 0.15 mm were measured respectively. Figure 8 and Fig. 9 As shown, the distance on the horizontal axis refers to the distance from the curved bottom of the U-shaped nickel-titanium wire of the final expansion device to the incisal edge of the maxillary incisor. Figure 8 and Fig. 9 By comparison, it can be seen that the diameter force of the expansion device with a U-shaped nickel-titanium wire diameter of 0.3 mm is too large, while the expansion device with a U-shaped nickel-titanium wire diameter of 0.15 mm is more suitable.

[0060] The present invention is not limited to the above-mentioned embodiments. If various changes or modifications to the present invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the scope of the claims and equivalent technologies of the present invention, the present invention is also intended to include these changes and modifications.

Claims

1. A method for constructing a mouse model of rapid maxillary expansion, characterized in that: The steps include the setup of the mouse model and the installation of the expansion device; The steps of installing the mouse model are as follows: (1) Anesthetizing mice; (2) The anesthetized mouse was fixed on the experimental table in a supine position, the head was raised, and the mouth was opened to expose the maxillary palate to the molar area; (3) pre-treating the maxillary incisor of the mouse, and making a retention groove on the mesiogingival distal side of the maxillary incisor using an electric carving knife; The steps of installing the expansion device are as follows: (1) Four ligatures with a diameter of 0.08 mm were cut and named as segments A and B, two each. One of the ligatures of segment A was passed through the gap between the two maxillary incisors and fixed at the retention groove of the neck of the incisor on one side. The same operation was performed on the maxillary incisor on the other side. (2) a section of nickel-titanium wire with a diameter of 0.15 mm was cut and bent into a teardrop shape with a distance of 1.4 cm from the bottom of the bend to the free end using a needle holder; (3) using the two sections of the B-section ligature wires to respectively ligate and fix the free ends of the nickel-titanium wire on the two sections of the A-section ligature wires, thereby respectively fixing the free ends of the nickel-titanium wire on the distal positions of the two maxillary incisors, so that the nickel-titanium wire forms a U-shape, and the nickel-titanium wire is close to the palate of the mouse and firmly fixed in its oral cavity; (4) A thin layer of fluid resin is applied to the free end of the nickel-titanium wire, the A-section ligature wire, the B-section ligature wire and the distal side of the maxillary incisor, and light-cured after trimming with a probe. The surface is polished with a grinder, and the free end of the nickel-titanium wire is trimmed so that the free end does not protrude outside the cured resin. At the same time, ensure that the distance from the bottom of the curve to the cutting edge of the maxillary incisor is 1 cm.

2. The method for constructing a mouse model of rapid maxillary expansion according to claim 1, characterized in that: The step (1) of installing the mouse model is to weigh the mouse and then perform anesthesia by intraperitoneal injection of 0.4% sodium pentobarbital at a dose of 0.12 mL / 10 g, and the disappearance of conjunctival reflex is used as a sign of successful anesthesia.

3. The method for constructing a mouse model of rapid maxillary expansion according to claim 1, characterized in that: The depth of the retention groove in step (3) of installing the mouse model is 0.5 mm.

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