Method for creating sd rat scar model and clinical research application in scar

Abstract

The application discloses a method for creating a SD rat scar model and a clinical research application in scars. By using the scar mechanics principle of E. Cerda, the process of human skin scar formation under the action of different direction tensile force is simulated, irregular wounds are made on the tail of rats, the integrity and compliance of skin, muscle and fascia are damaged, and proliferative scars can be formed by regular dressing change without any auxiliary equipment. The proliferative scar reduces the degree of proliferation after a period of time, but the scar can be permanently retained, which well simulates the formation and development process of human proliferative scar. Compared with the traditional method, the preparation process of the improved scar model is simpler, the cost is lower, and the processing difficulty and time cost are reduced. The model does not need to use any mechanical device or chemical substance to induce scar formation, which reduces the operation difficulty and the dependence on additional materials. The improved scar model has high reproducibility. By manufacturing irregular wounds, the formation of the model can be better controlled and reproduced, and the reliability of experimental results is improved.

Description

Technical Field

[0001] This application relates to the field of biomedical technology, and more specifically, to a method for creating an SD rat scar model and its clinical application in scar research. Background Technology

[0002] Scarring, as a natural response to severe trauma in animals, is a common healing outcome of skin damage. However, this healing process is often accompanied by functional impairment and cosmetic defects, negatively impacting the animal's quality of life. In the biomedical field, exploring the mechanisms of scarring and developing effective prevention and treatment strategies has become an important research topic.

[0003] 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-muscular structure of animal skin causes wounds to heal primarily through contraction, which differs from the healing pattern of human skin. This characteristic necessitates traditional methods of constructing animal scar models that rely on drugs to promote scar formation. This not only increases the complexity of experiments but also risks that residual drugs may interfere with the research data, affecting the accuracy of the results.

[0004] In recent years, scientific research has shown that scar formation is a complex process involving multiple factors. Among them, wound tension is one of the key factors influencing scar formation. By applying appropriate tension to the wound during the healing process, the natural formation of scars can be promoted, thereby avoiding potential interference from drug use.

[0005] Currently, the main rodent models of scarring include the following: rat wound splint fixation HTS (hypertrophic scar) model, human xenograft nude mouse HTS model, and HTS model involving the removal of abdominal wall muscles in mice. These models provide a foundation for scar research to some 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 they lack an immune response;

[0009] 4. Splints are inconvenient to use, and it is difficult to use them to immobilize active animals;

[0010] 5. Insufficient model stability.

[0011] Furthermore, no model of scarring in rodents has yet been developed under physiological conditions without the use of any equipment or chemicals.

[0012] Given the many shortcomings of existing animal models, developing an ideal animal model is crucial to supporting research related to scar formation and treatment. Summary of the Invention

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

[0014] To achieve the above objectives, this application provides the following technology:

[0015] This invention provides a method for creating a scar model in SD rats, comprising the following steps:

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

[0017] S2. Following the scar biomechanics test model proposed by E. Cerda, 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 part of the tail to obtain the SD rat scar model.

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

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

[0021] The surgical area was defined as the region 4±2 cm from the mid-tail of the SD rat.

[0022] Disinfect the surgical area with iodine solution.

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

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

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

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

[0027] A second annular wound is created 2±0.5cm below the first annular wound surface;

[0028] Between the first annular wound and the second annular wound, several skin defects with a width of 0.6±0.2cm and a depth to the fascia are uniformly excised in a circular pattern along the direction of the rat's tail.

[0029] A scar wound model was obtained in SD rats.

[0030] Preferably, the skin defect is irregular, and the force on the wound comes from different directions.

[0031] Preferably, in step S3, the surgical healing treatment includes: applying erythromycin ointment to the wound for external healing treatment, 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] This invention also provides a method for creating an SD rat scar model for clinical research applications in scar treatment.

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

[0035] This invention utilizes E. Cerda's principles of scar mechanics to simulate the tensile forces acting in different directions during human scar formation. It creates irregular wounds on the tail of rats, simultaneously disrupting the integrity and compliance of the skin, muscles, and fascia. Hypertrophic scars form after routine dressing changes, eliminating the need for any auxiliary equipment. The hypertrophic scars reduce in size over time but remain permanently, effectively mimicking the formation and development of hypertrophic scars in humans. Advantages of the improved design:

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

[0037] 2. Simulation of Human Scar Formation: This model can better simulate the formation process of human scars, thus providing more accurate experimental results. By disrupting the integrity and compliance of the skin and tissues, 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 the dependence on additional materials.

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

[0040] 5. High practicality: The model is relatively simple to establish and easy to implement, and can be widely used in research related to scar formation. It provides an important tool for further research on the pathogenesis and treatment strategies of scars. Attached Figure Description

[0041] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of the accompanying drawings are used to explain the application and do not constitute an undue limitation of the application. In the drawings:

[0042] Figure 1 This is a schematic diagram of the principle of the scar biomechanical test model referenced in this invention;

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

[0044] Figure 3 These are schematic diagrams 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 cell morphology changes under a microscope on a new three-dimensional culture substrate, simulating the changes in the magnitude and direction of tension of skin fibroblasts. Detailed Implementation

[0046] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0047] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

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

[0049] This invention provides a method for creating a scar model in SD rats, comprising the following steps:

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

[0051] S2. Following the scar biomechanics test model proposed by E. Cerda, 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 part of the tail to obtain the SD rat scar model.

[0053] Currently, no rodent scar model has been developed under physiological conditions without the use of any equipment or chemicals. Therefore, the purpose of this study is to establish a rat model of scar formation induced by mechanical devices or chemicals, which has not been reported in the literature at home and abroad.

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

[0055] 1. To develop a model of scar formation in rodents under physiological conditions without the use of any equipment or chemicals, in order to fill a 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 human scar formation process, so as to study the pathogenesis and treatment of scars more accurately.

[0058] Therefore, this invention aims to establish a rat model for inducing scar formation without relying on mechanical devices or chemical substances. This model, under physiological conditions, requires no equipment or chemicals and is expected to solve the problems existing in current models. Currently, no such model has been reported in domestic or international literature. This patent is expected to provide a more ideal, stable, and easy-to-operate animal model for scar research.

[0059] The scar mechanics testing model proposed by E. Cerda simulates the process of scar formation in human skin under tensile forces from different directions. It creates irregular wounds on the tails of rats, simultaneously disrupting the integrity and compliance of the skin, muscles, and fascia, thus mimicking the human scar formation process. This model demonstrates excellent performance in terms of scar formation and stability, providing a reliable research tool for scar research and treatment.

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

[0061] This invention constructs a scar model of the tail of SD mice based on this model. By increasing wound tension (different scar models can be constructed by referring to the steps of this invention, thereby successfully changing the direction and magnitude of tension in rat skin wounds by designing wounds of different shapes, thus forming a stable SD rat scar model), the direction of tension is changed, and wound contraction is restricted to achieve natural scar formation. By controlling different wounds and changing the magnitude and direction of wound tension, the natural state of scar formation in human skin during wound healing is effectively simulated. Experimental results show that this model can produce consistent and reproducible scars, which is crucial for studying the mechanism of scar formation, its progression, and evaluating the efficacy of different treatment methods.

[0062] Specific creation steps:

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

[0064] - SD rats aged 4-6 weeks were selected as experimental animals.

[0065] - The area approximately 4 cm from the midpoint of the rat's tail was designated as the surgical area.

[0066] Step Two: Disinfection and Initial Incision Preparation

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

[0068] - In the disinfected surgical area of ​​the rat tail, a ring of skin approximately 0.8 cm wide is removed, cutting down to the fascia layer (e.g. Figure 2 A).

[0069] Step 3: Making the auxiliary incision

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

[0071] Step 4: Skin Defect Creation

[0072] Between the two circular incisions (i.e., the first and second circular wounds), several strips of skin, each about 0.6 cm wide, are vertically removed to create a skin defect extending to the fascia layer.

[0073] - Ensure that vertical incisions are straight and that the incisions are not parallel or nearly parallel to each other, in order to avoid the stress direction being the same during the wound healing process and direct bridging of the skin for healing.

[0074] Step 5: Postoperative care and observation

[0075] - Routine wound dressing changes are performed after surgery, once every 1-2 days.

[0076] - Apply erythromycin ointment topically to promote wound healing.

[0077] - Observe the recovery of the rat's wounds daily and take photos to record the process.

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

[0079] - Ensure that rats have free access to water and food throughout the experiment.

[0080] condition:

[0081] During the experiment, the laboratory temperature should be maintained between 22-25℃ and the relative humidity 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 scar research and treatment.

[0083] Using the above method, this application utilizes E. Cerda's scar mechanics principles to simulate the tensile forces acting in different directions during human skin scar formation, creating irregular wounds on the rat tail while simultaneously disrupting the integrity and compliance of the skin, muscles, and fascia. Through this method, the present invention successfully establishes a stable SD rat scar model that can simulate the formation process of human scars, providing a new tool for scar research. Enhanced functionality and achieved effects: The rat scar model provided by this patent does not rely on external equipment or chemicals, reducing experimental costs and simplifying the operational process. The model's stability improves the reliability of experimental results, contributing to better consistency and reproducibility of data. 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 novel treatment strategies. The establishment of this model is expected to promote the development of the field of scar treatment, providing scientific evidence and technical support for improving the quality of life of affected individuals.

[0084] The application research of this invention will be explained below in conjunction with animal model experiments.

[0085] The specific design and construction of different scar models can be carried out by referring to the above steps to design wounds of different shapes, thereby changing the direction and magnitude of tension in the rat skin wounds and forming SD rat scar models with different requirements. The specific number of models required can be prepared according to experimental needs and the requirements of the experimenters.

[0086] As attached Figure 2 The diagram shown illustrates the healing process of scars at different stages. Figure 2 A represents the first cut along the designated line to create the opening surface; Figure 2 B represents scar tissue that formed two months after the wound healed; Figure 2 C represents scar tissue that formed 6 months after the wound healed.

[0087] As attached Figure 3 The image shows a microscopic illustration of tissues from a normal rat model and the SD rat scar model of this invention under staining, wherein: Figure 3 A: Normal rat tail skin tissue; Figure 3 B: Scar tissue two months after the wound healed; Figure 3 C: Scar tissue 6 months after wound healing. Figure 3 A, 3B, and 3C were stained with hematoxylin and eosin, while 3D, 3E, and 3F were stained with Masson stain. The comparison revealed that, compared to normal skin tissue, scar tissue exhibited reduced hair follicles, excessive fibroblast proliferation, increased capillary numbers, thicker, denser, and more tightly packed collagen fibers, and excessive extracellular matrix deposition.

[0088] As attached Figure 4 The diagram illustrates changes in cell morphology. In the figure: 4A: Cell morphology changes on a fresh three-dimensional culture medium under a microscope 5 hours after Dil staining; 4B: Cell morphology changes on a collagen gel matrix under a microscope 5 hours after Dil staining; 4C: Cell morphology changes on a collagen matrix under a microscope 5 hours after Dil staining; 4D: Cell morphology changes on a floating collagen gel matrix under a microscope 5 hours after Dil staining. Cell experiments showed that human skin fibroblasts (third generation) exhibited a dendritic structure after 5 hours in a dish containing rat tail collagen gel (subsequent controls were also 5 hours). Figure 4 B. Gradually release tension in all directions; the more tension is released, the smaller the cell becomes, and the fewer and shorter its dendrites become. Figure 4 When there is absolutely no tension, the cells are spindle-shaped (normal morphology). Figure 4A) Without tension reduction, the rat tail collagen in the final dish becomes porous, and cell tension also decreases. This indicates that the cell's response to force is related to tension, and fibroblasts are the main cells under stress. This cell experiment demonstrates the significant effect of tension on cell morphology; in the collagen matrix, fibroblasts are dendritic, and their contraction may be the beginning of wound remodeling, ultimately forming scars.

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

[0090] This method not only provides an animal model that more closely resembles natural scar formation but also helps 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 in this patent, researchers can better explore the mechanisms of scar formation and progression, and develop more effective prevention and treatment methods, providing a scientific basis for clinical treatment.

[0091] This model employs a novel, reproducible approach that offers greater flexibility and practicality compared to traditional methods that rely on equipment or chemicals.

[0092] This model enables tool-free wound creation: This study is the first to propose creating multiple irregular wounds in rats without the aid of any tools. By disrupting the integrity and compliance of the skin, muscles, and fascia, it simulates the tension in various directions that occurs during scar formation, thereby reducing the rat's wound contraction ability.

[0093] This invention enables stable scar formation: using the innovative method described above, stable scars were formed on the tail of rats. These scars are characterized by long-term persistence and closely mimic the morphology and characteristics of human scars. This innovation validates the crucial role of biomechanics in scar formation and provides a powerful tool for further research into the pathogenesis and treatment strategies of scars.

[0094] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for creating a scar model in SD rats, characterized in that, Includes the following steps: S1. Prepare SD rats and perform tail surgery pretreatment, including: SD rats aged 4-6 weeks were selected as experimental animals; The surgical area was defined as the region 4±2 cm from the mid-tail of the SD rat. Disinfect the surgical area with povidone-iodine; S2. Referring to the scar biomechanics test model proposed by E. Cerda, corresponding scar surgery was performed on the tail of SD rats, including: The scar biomechanics test model proposed by E. Cerda was pre-set as a reference model; Referring to the aforementioned scar biomechanical test model, corresponding scar surgery was performed on the tail of SD rats: In the surgical area, a first annular wound with a width of 0.8±0.2cm and a depth to the fascia was excised; A second annular wound is created 2±0.5cm below the first annular wound surface; Between the first annular wound and the second annular wound, several skin defects with a width of 0.6±0.2cm and a depth to the fascia are uniformly excised circumferentially along the length of the rat's tail; wherein, the skin defects are straight incisions and the incisions are not parallel or approximately parallel. A scar wound model was obtained in SD rats; S3. Surgical healing treatment: After healing, repeat the above steps to perform corresponding scar surgery on the remaining part of the tail to obtain the SD rat scar model.

2. The method for creating an SD rat scar model as described in claim 1, characterized in that, In step S3, surgical healing treatment includes: applying erythromycin ointment to the wound for external healing treatment, and changing the dressing once every 1-2 days after the operation.

3. The method for creating an SD rat scar model as described in claim 1, characterized in that, The method maintains the laboratory temperature at 22-25°C and the relative humidity at 40%-70%.

4. The clinical application of the method for creating an SD rat scar model according to any one of claims 1-3 in scar research.

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