Method for creating scar model of SD (Sprague Dawley) rat and clinical research application of scar model in scar

Abstract

The invention discloses an SD (Sprague Dawley) rat scar model creating method and clinical research application in scars, by utilizing the scar mechanics principle of E.Cerdes, the action of pulling forces in different directions in the human skin scar forming process is simulated, irregular wounds are made at the tail of a rat, the integrity and compliance of skin, muscles and fascia are damaged, and the scar model is obtained. Hypertrophic scars can be formed by frequently and regularly changing dressings, and any auxiliary equipment is not needed any more. The hyperplasia degree of the hypertrophic scar is reduced after a period of time, but the scar can be permanently reserved, so that the formation and development process of the human hypertrophic scar is well simulated. Compared with a traditional method, the preparation process of the improved scar model is simpler, the cost is lower, and the treatment difficulty and time cost are reduced. The model does not need to use any mechanical device or chemical substance to induce scar formation, so that the operation difficulty and the dependence on additional materials are reduced. The improved scar model has high replicability. By manufacturing the irregular wound surface, the formation of the model can be better controlled and reproduced, and the reliability of an experimental result is improved.

Description

Technical Field

[0001] The present application relates to the field of biomedical technology, and in particular to a method for creating a SD rat scar model and its clinical research application in scars. Background Art

[0002] Scars are a natural response of animals to severe trauma and are a common healing result of the skin after severe damage. However, this healing process is often accompanied by functional disorders and appearance defects, which have a negative impact on the quality of life of animals. In the biomedical field, exploring the mechanism of scar formation and developing effective prevention and treatment strategies have become an important research topic.

[0003] In order to gain a deeper understanding of the scar formation process and evaluate potential prevention and treatment methods, animal models have become the most commonly used research tool for researchers. However, the unique lipid membrane muscle structure in animal skin causes the wound surface to often contract during the healing process, which is different from the healing pattern of human skin. This feature leads to the need for traditional animal scar model construction methods to rely on drugs to promote scar formation, which not only increases the complexity of the experiment, but also residual drugs may interfere with the research data and affect the accuracy of the experimental results.

[0004] In recent years, scientific studies have shown that scar formation is a complex process involving multiple factors. Among them, wound tension is one of the key factors affecting scar formation. By applying appropriate tension to the wound surface during the healing process, the natural formation of scars can be promoted, thus avoiding potential interference caused by the use of drugs.

[0005] At present, the scar mouse models mainly include the following: rat wound splint fixation HTS (hypertrophic scar) model, human xenograft nude mouse HTS model, mouse abdominal wall muscle resection HTS model, etc. These models provide a basis for scar research to a certain extent, but the following problems still exist:

[0006] 1. High cost and difficult to handle;

[0007] 2. Lack of healing response;

[0008] 3. Nude mice are difficult to maintain and lack immune response;

[0009] 4. The splint is inconvenient to use and it is difficult to fix active animals with a splint;

[0010] 5. The model is not stable enough.

[0011] Furthermore, no models of scarring following injury have been developed in rodents under physiological conditions without the use of any equipment or chemicals.

[0012] Since existing animal models have many shortcomings, developing an ideal animal model is crucial to support research related to scar formation and treatment. Summary of the invention

[0013] The main purpose of this application is to provide a method for establishing a SD rat scar model and its clinical research application in scars to solve current problems.

[0014] In order to achieve the above objectives, this application provides the following technologies:

[0015] The present invention provides a method for establishing a SD rat scar model, comprising the following steps:

[0016] S1. Prepare SD rats and perform tail surgery pretreatment;

[0017] S2. According to the scar mechanical test model proposed by E. Cerda, the corresponding scar surgery was performed on the tail of SD rats;

[0018] S3. Surgical healing treatment: after healing, repeat the above steps to perform corresponding scar surgery on the remaining parts of the tail to obtain the SD rat scar model.

[0019] Preferably, S1, preparing SD rats and performing tail surgery pretreatment, comprising:

[0020] 4-6 weeks old SD rats were selected as experimental animals;

[0021] The area 4±2 cm near the middle of the tail of the SD rat was determined as the surgical operation area;

[0022] Disinfect the surgical area with iodine.

[0023] Preferably, S2, referring to the scar mechanical test model proposed by E. Cerda, a corresponding scar surgery is performed on the tail of SD rats, including:

[0024] The scar mechanical test model proposed by E. Cerda was pre-set as the reference model;

[0025] Referring to the scar mechanical test model, the corresponding scar surgery was performed on the tail of SD rats:

[0026] In the surgical operation area, the first circular wound with a width of 0.8 ± 0.2 cm and a depth to the fascia was excised;

[0027] Making a second annular wound surface at a position 2±0.5 cm below the first annular wound surface;

[0028] Between the first annular wound surface and the second annular wound surface, several skin incisions with a width of 0.6±0.2 cm and a depth to the fascia were evenly excised in a circular manner in the vertical direction of the rat's tail;

[0029] The scar wound model of SD rats was obtained.

[0030] Preferably, the skin defect is irregular, and the wound is subjected to forces from different directions.

[0031] Preferably, in step S3, the surgical healing treatment includes: using erythromycin ointment to perform external healing treatment on the wound surface, and changing the dressing once every 1-2 days after the operation.

[0032] Preferably, the method maintains the laboratory temperature at 22-25°C and the relative humidity at 40%-70%.

[0033] The present invention also provides a method for establishing a SD rat scar model for clinical research application in scars.

[0034] Compared with the prior art, this application can bring the following technical effects:

[0035] The present invention utilizes the scar mechanics principle of E. Cerda to simulate the tension in different directions during scar formation on human skin, and creates irregular wounds on the rat's tail, while destroying the integrity and compliance of the skin, muscles and fascia. Hypertrophic scars can be formed through routine dressing changes, and no auxiliary equipment is required. The hypertrophic scar will decrease in degree after a period of time, but the scar can be permanently retained, which well imitates the formation and development process of human hypertrophic scars. Advantages of the improved method:

[0036] 1. Low cost and easy processing: Compared with traditional methods, the preparation process of the improved scar model is simpler and less expensive, reducing the processing difficulty and time cost.

[0037] 2. Simulate human scar formation: This model can better simulate the process of human scar formation, thus providing more accurate experimental results. By destroying the integrity and compliance of skin and tissue, the model can more realistically reflect the physiological characteristics of scars.

[0038] 3. No reliance on equipment or chemicals: Compared with other methods, this model does not require the use of any mechanical devices or chemicals to induce scar formation, reducing the difficulty of operation and reliance on additional materials.

[0039] 4. Strong replicability: The improved scar model has high replicability. By creating irregular wound surfaces, the formation of the model can be better controlled and reproduced, thus improving the reliability of the experimental results.

[0040] 5. Strong practicability: The model is relatively simple to establish and easy to implement, and can be widely used in scar formation-related research. It provides an important tool for further studying the pathogenesis and treatment strategies of scars. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0042] Figure 1 This is a schematic diagram of the principle of the scar mechanical test model referred to in the present invention;

[0043] Figure 2 It is a schematic diagram of the recovery state of the SD rat scar model of the present invention at different healing stages;

[0044] Figure 3 It is a schematic diagram of the tissue morphology of the normal rat model and the SD rat scar model under a microscope;

[0045] Figure 4 This is a schematic diagram of the changes in cell morphology of skin fibroblasts on a new three-dimensional culture matrix under a microscope that simulates changes in the magnitude and direction of tension. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0047] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0048] The experimental reagents, equipment, environment, etc. involved in the present invention can all be provided by an animal laboratory, and this embodiment does not limit this.

[0049] The present invention provides a method for establishing a SD rat scar model, comprising the following steps:

[0050] S1. Prepare SD rats and perform tail surgery pretreatment;

[0051] S2. According to the scar mechanical test model proposed by E. Cerda, the corresponding scar surgery was performed on the tail of SD rats;

[0052] S3. Surgical healing treatment: after healing, repeat the above steps to perform corresponding scar surgery on the remaining parts of the tail to obtain the SD rat scar model.

[0053] The present invention has not yet developed a model of scarring after injury in rodents under physiological conditions without the use of any equipment or chemicals. Therefore, the purpose of this study is to establish a rat model that does not rely on mechanical devices or chemicals to induce scarring, which has not been reported in literature at home and abroad.

[0054] The purpose of the present invention is to solve the following technical problems:

[0055] 1. To develop a model of scar formation after injury in rodents under physiological conditions without the use of any equipment or chemicals to fill the gap in existing research.

[0056] 2. To establish a rat model of scar formation that does not rely on mechanical devices or chemical substances to improve the stability and reliability of the model.

[0057] 3. To provide an animal model that can simulate the scar formation process in humans, so as to more accurately study the pathogenesis and treatment of scars.

[0058] Therefore, the present invention aims to establish a rat model that does not rely on mechanical devices or chemicals to induce scar formation. This model does not require the use of any equipment or chemicals under physiological conditions and is expected to solve the problems of existing models. At present, there is no literature report on such a model at home and abroad. The proposal of this patent is expected to provide a more ideal, stable and easy-to-operate animal model for scar research.

[0059] The scar mechanical test model proposed by E. Cerda simulates the tensile forces in different directions during the scar formation process of human skin, creates irregular wounds on the rat's tail, and destroys the integrity and compliance of the skin, muscles and fascia, simulating the scar formation process of the human body. This model shows excellent performance in scar formation and stability, providing a reliable research tool for the study and treatment of scars.

[0060] As attached Figure 1Shown is the scar mechanics test model proposed by E. Cerda. (a) The dotted lines represent the inner and outer boundaries of the circular plate supporting the elastic membrane (scar mechanics test model). Note that there is a circular hole with radius a in the center of the plate. The black dots represent small circles of adhesion where the fishing lines are attached to the membrane. Each fishing line runs on a low-friction roller to a suspended weight (not shown). An additional weight is attached below the center of the membrane. (b) A close-up view of the deformed membrane after applying a central force. (c) Schematic diagram of the membrane under plane stress deformation. A constant tension is applied to the outer boundary and a tensile stress is applied at the location of the hole.

[0061] The present invention constructs a scar model on the tail of SD mice with reference to the model, and by increasing the tension of the wound surface (the steps of the present invention can be referred to to construct different scar models, thereby successfully changing the tension direction and magnitude of the rat skin wound surface by designing wound surfaces of different shapes, thereby forming a stable SD rat scar model), changing the direction of tension, and limiting wound contraction to achieve the natural formation of scars. By controlling different wound surfaces and changing the magnitude and direction of tension of the wound surface, the natural state of scar formation in human skin during the wound healing process is effectively simulated. The experimental results show that the model can produce consistent and repeatable scars, which is crucial for studying the mechanism and progression of scars and evaluating the efficacy of different treatment methods.

[0062] Specific creation steps:

[0063] Step 1: Selection and preparation of experimental animals

[0064] - 4-6 week old SD rats were selected as experimental animals.

[0065] - The area about 4 cm proximal to the middle of the rat's tail was determined as the surgical operation area.

[0066] Step 2: Disinfection and initial incision

[0067] - Thoroughly disinfect the surgical area using 2% iodine solution.

[0068] - In the sterilized rat tail surgical area, a circular skin cut of about 0.8 cm in width was made to the fascia layer (such as Figure 2 A).

[0069] Step 3: Auxiliary incision making

[0070] - Make another identical circular incision approximately 2 cm below the initial circular skin incision.

[0071] Step 4: Skin defect creation

[0072] - Between the two circular incisions (i.e., the first circular wound surface and the second circular wound surface), several strips of skin with a width of about 0.6 cm were vertically removed to form a skin defect, the depth of which reached the fascia layer.

[0073] - Ensure that the vertical incisions are straight and not parallel or nearly parallel to each other to avoid the same force direction during wound healing and direct skin bridging healing.

[0074] Step 5: Postoperative care and observation

[0075] -Change the wound dressing routinely after surgery, once every 1-2 days.

[0076] -Use erythromycin ointment for external use to promote wound healing.

[0077] -Observe the recovery of the rats' wounds every day and take photos to record them.

[0078] - If the wound healing effect is not satisfactory, some of the skin that was not removed last time can be removed again after the wound is completely healed.

[0079] - During the entire experiment, rats were given free access to water and food.

[0080] condition:

[0081] -During the experiment, the laboratory temperature should be maintained at 22-25℃ and the relative humidity should be maintained between 40%-70% to provide a suitable experimental environment.

[0082] Through the above technical solution, this patent can effectively establish a stable rat scar model, providing a strong experimental basis for the research and treatment of scars.

[0083] Using the above method, the present application utilizes the scar mechanics principle of E. Cerda to simulate the tension in different directions during the scar formation process of human skin, create irregular wounds on the rat's tail, and destroy the integrity and compliance of the skin, muscle and fascia. Through the above method, the present invention successfully established a stable SD rat scar model, which can simulate the formation process of human scars and provide a new tool for the study of scars. Added functions and achieved effects: The rat scar model provided by this patent does not need to rely on external equipment or chemicals, reduces experimental costs, and simplifies the operation process. The stability of the model improves the reliability of experimental results and helps to obtain data with better consistency and repeatability. By simulating the formation process of human scars, this model provides an effective experimental platform for studying the pathogenesis of scars, evaluating treatment methods, and developing new treatment strategies. The establishment of this model is expected to promote the development of the field of scar treatment and provide scientific basis and technical support for improving the quality of life of affected individuals.

[0084] The application research of the present invention will be described below in conjunction with animal model experiments.

[0085] To design and construct different scar models, you can refer to the above steps to design wounds of different shapes, change the tension direction and magnitude of the rat skin wound, and form SD rat scar models with different needs. The specific number of models required can be prepared according to the experimental needs and the requirements of the experimenter.

[0086] As attached Figure 2 The figure shows a schematic diagram of scar healing experiment at different stages, where: Figure 2 A is the first cutting surface along the setting line; Figure 2 B is the scar tissue formed 2 months after the wound healed; Figure 2 C is the scar tissue formed 6 months after the wound healed.

[0087] As attached Figure 3 The figure shows the microscopic diagram of the tissues of the normal rat model and the SD rat scar model of the present invention under staining, wherein: Figure 3 A: Normal rat tail skin tissue; Figure 3 B: Scar tissue 2 months after wound healing; Figure 3 C: Scar tissue 6 months after wound healing. Figure 3 A, 3B and 3C were stained with hematoxylin-eosin, and 3D, 3E and 3F were stained with Masson's stain. Compared with normal skin tissue, scar tissue has fewer hair follicles, excessive fibroblast proliferation, increased number of capillaries, thicker, denser and more dense collagen fibers, and excessive deposition of extracellular matrix.

[0088] As attached Figure 4 The figure shows the schematic diagram of the changes in cell morphology. In the figure: 4A: Changes in cell morphology on a new three-dimensional culture matrix under the microscope after 5 hours of Dil staining; 4B: Changes in cell morphology on a collagen gel matrix under the microscope after 5 hours of Dil staining; 4C: Changes in cell morphology on a collagen matrix under the microscope after 5 hours of Dil staining; 4D: Changes in cell morphology on a floating collagen gel matrix under the microscope after 5 hours of Dil staining. Cell experiments found that human skin fibroblasts (third generation) in rat tail collagen gel vessels for 5 hours (other controls were all 5 hours later) showed dendritic shapes, such as Figure 4 B. Gradually release tension in all directions. The more tension is released, the smaller the cell becomes, and its dendrites also gradually decrease and shorten ( Figure 4 D, C), when there is no tension at all, the cell is spindle-shaped (normal morphology) ( Figure 4A) If tension is not reduced, the rat tail collagen in the vessel will eventually become porous and the cell tension will also decrease. This indicates that the cell's response to force is related to tension, and fibroblasts are the main cells of stress. This cell experiment shows that tension has a significant effect on cell morphology. In the collagen matrix, fibroblasts are dendritic, and their contraction may be the beginning of wound remodeling, and finally form scars.

[0089] Therefore, the SD rat scar model and its preparation method provided by this patent provide a new and effective scar model for the research and treatment of scars. Its stability and reliability make this model an important tool for scar experimental research, which is expected to promote the development of scar treatment technology and contribute to improving the quality of life of patients.

[0090] This method can not only provide an animal model of scar formation that is closer to the natural state, but also help reduce the interference of drugs on experimental results, thus providing a more reliable and accurate model for experimental research on scars. Through the method provided by this patent, researchers can better explore the mechanism of scar occurrence and progression, and develop more effective prevention and treatment methods, providing a scientific basis for clinical treatment.

[0091] This model uses a new, reproducible approach that offers greater flexibility and practicality than traditional methods that rely on equipment or chemicals.

[0092] This model does not rely on tools for wound creation: This study proposed for the first time to create multiple irregular wounds on rats without the help of any tools. By destroying the integrity and compliance of the skin, muscles and fascia, the skin is simulated to be subjected to tension in all directions during scar formation, thereby reducing the rat's wound contraction ability.

[0093] The present invention can achieve stable scar formation: Through the above innovative method, a stable scar was formed on the tail of a rat. This scar has the characteristics of long-term existence and better simulates the morphology and characteristics of human scars. This innovation verifies the important role of biomechanics in the scar formation process and provides a powerful tool for further research on the pathogenesis and treatment strategies of scars.

[0094] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for establishing a scar model in SD rats, characterized in that: The steps include: S1. Prepare SD rats and perform tail surgery pretreatment; S2. According to the scar mechanical test model proposed by E. Cerda, the corresponding scar surgery was performed on the tail of SD rats; S3. Surgical healing treatment: after healing, repeat the above steps to perform corresponding scar surgery on the remaining parts of the tail to obtain the SD rat scar model.

2. The method for establishing a SD rat scar model according to claim 1, wherein: S1. Prepare SD rats and perform tail surgery pretreatment, including: 4-6 weeks old SD rats were selected as experimental animals; The area 4±2 cm near the middle of the tail of the SD rat was determined as the surgical operation area; Disinfect the surgical area with iodine.

3. The method for establishing a SD rat scar model according to claim 2, wherein: S2. According to the scar mechanical test model proposed by E. Cerda, the corresponding scar surgery was performed on the tail of SD rats, including: The scar mechanical test model proposed by E. Cerda was pre-set as the reference model; Referring to the scar mechanical test model, the corresponding scar surgery was performed on the tail of SD rats: In the surgical operation area, the first circular wound with a width of 0.8 ± 0.2 cm and a depth to the fascia was excised; Making a second annular wound surface at a position 2±0.5 cm below the first annular wound surface; Between the first annular wound surface and the second annular wound surface, several skin incisions with a width of 0.6±0.2 cm and a depth to the fascia are evenly excised in a circular manner in the vertical direction of the rat's tail; The scar wound model of SD rats was obtained.

4. The method for establishing a SD rat scar model according to claim 3, wherein: The skin defect is irregular, and the wound is subjected to forces from different directions.

5. The method for establishing a SD rat scar model according to claim 1, characterized in that: In step S3, the surgical healing treatment includes: using erythromycin ointment to perform external healing treatment on the wound surface, and changing the dressing once every 1-2 days after the operation.

6. The method for establishing a scar model in SD rats according to claim 1, characterized in that: The method maintains the laboratory temperature at 22-25° C. and the relative humidity at 40%-70%.

7. Application of the method for establishing a SD rat scar model according to any one of claims 1 to 6 in clinical research on scars.

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