Method for establishing rat radiodermatitis model

Abstract

The invention discloses a method for establishing a rat radiodermatitis model. The method comprises the following steps: S1, setting a control group, a low-dose group, a medium-dose group, a high-dose group and a false irradiation group; the control group is not irradiated, and the skin state of the rats under the condition that the rats are not damaged by radiation is observed; the total irradiation dose of the low-dose group is 35Gy; the total irradiation dose of the medium dose group is 40Gy; the total irradiation dose of the high-dose group is 45Gy; s2, selecting rats, shaving and cleaning radiation parts of the rats, and performing anesthesia treatment on the rats; s3, a 6MeV electron accelerator is adopted for radiation irradiation, the irradiation time of a low-dose group is 5.83 minutes, the irradiation time of a medium-dose group is 6.67 minutes, and the irradiation time of a high-dose group is 7.5 minutes; s4, after irradiation is completed, the rats are removed and transferred into a clean cage, the reaction of the rats after irradiation is observed, and the initial conditions of skin injuries including erythema and swelling are recorded; experiments should regularly record the health condition of the rat.

Description

Technical Field

[0001] The invention relates to the field of radiation dermatitis, and in particular to a method for establishing a rat radiation dermatitis model. Background Art

[0002] Radiation dermatitis is one of the common side effects during radiotherapy, which manifests as skin erythema, edema, ulcers, scabs and other symptoms, seriously affecting the patient's quality of life.

[0003] The construction of an animal model of radiation dermatitis has many important meanings: first, in medical research, it helps to deeply explore the pathogenesis of the disease, including cellular and inflammatory response mechanisms, and provides a platform for drug development screening and treatment evaluation; second, in radiation protection research, it can evaluate the effectiveness of protective materials and the best application method; third, it can clarify the relationship between radiation dose and the degree of skin damage, and provide a reference for determining the safe dose range for radiotherapy, so as to balance tumor treatment and normal skin protection.

[0004] Therefore, establishing an effective animal model is of great significance for studying the pathogenesis of radiation dermatitis and evaluating prevention and treatment measures.

[0005] Although the existing rat radiation dermatitis model has certain application value, there are still some problems, such as inconsistent irradiation doses, inadequate model group settings, and insufficient observation periods.

[0006] Specifically, there are multiple problems in the study of radiation dermatitis animal models, which affect the accuracy and reliability of experimental results. First, the irradiation dose is inconsistent. The difference in doses used in different studies leads to different onset time, severity and pathological characteristics, making it difficult to compare and integrate data.

[0007] Secondly, the model group setting was not detailed enough, and there was a lack of precise grouping of factors such as animal age, gender, and skin type, which may lead to the experimental results being mixed with multiple factors and affect the evaluation of the treatment effect.

[0008] Third, the observation period of some studies was too short and failed to fully evaluate the overall development and long-term complications of radiation dermatitis, which may overestimate or underestimate the effect of the drug.

[0009] Fourth, the types and energies of radiation are not uniform, resulting in differences in the types and degrees of skin damage simulated by the model, affecting the understanding of pathological mechanisms and treatment strategies.

[0010] Fifth, if protective measures are not standardized, radiation exposure to skin in non-target areas may interfere with experimental results and affect the accurate assessment of skin damage.

[0011] Finally, the evaluation indicators are single or incomplete, ignoring skin histology and molecular biology indicators, and are unable to deeply reflect pathological changes and treatment effects, resulting in an incomplete understanding of radiation dermatitis and an incomplete evaluation of treatment effects.

[0012] Therefore, it is necessary to provide a more accurate, detailed and experimentally feasible method for establishing a radiation dermatitis model. Summary of the invention

[0013] The purpose of the present invention is to solve the deficiencies in the prior art and to provide a method for establishing a rat radiation dermatitis model with a short cycle, low cost, good reproducibility, simple operation and a modeling method close to clinical practice.

[0014] In order to solve the above technical problems, the technical method adopted by the present invention is as follows: The present invention discloses a method for establishing a rat radiation dermatitis model, comprising the following steps:

[0015] S1. Set up a control group, a low-dose group, a medium-dose group, a high-dose group and a sham irradiation group; the control group was not irradiated, and the skin condition of the rats was observed without radiation damage; the total irradiation dose of the low-dose group was 35 Gy; the total irradiation dose of the medium-dose group was 40 Gy; the total irradiation dose of the high-dose group was 45 Gy;

[0016] S2. Rats were selected, and the irradiated areas of the rats in the low-dose group, medium-dose group, high-dose group, and sham-irradiation group were shaved and cleaned, and the rats were anesthetized;

[0017] S3. A 6MeV electron accelerator was used for radiation irradiation. The irradiation time for the low-dose group was 5.83 minutes, the irradiation time for the medium-dose group was 6.67 minutes, and the irradiation time for the high-dose group was 7.5 minutes.

[0018] S4. After irradiation, remove the rat and transfer it to a clean cage, observe the rat's reaction after irradiation, and record the initial condition of skin damage, including skin erythema and swelling; the experimenter should regularly record the health status of the rat, including weight changes, appetite, and activity status.

[0019] Furthermore, in step S3, the rats are placed in a lead box, which includes a plurality of rat placement slots and a lead plate cover placed on top of the rat placement slots; the lead plate cover is provided with radial holes matching the rat placement slots, and the shaved parts of the rats are placed under the radial holes.

[0020] Furthermore, the radiation hole is a circular hole with a diameter of 3 cm.

[0021] Furthermore, the lead box is composed of a stainless steel box with a length of 28 cm, a width of 28 cm, and a height of 7 cm, and the lead box is divided into four rat placement slots with a width of 7 cm by iron sheets.

[0022] Furthermore, the observation period after irradiation was 60 days; during this period, the progression of skin damage in rats was observed weekly to assess whether typical manifestations of radiation dermatitis such as erythema, edema, ulcers, or crusting appeared; the wound recovery was recorded by visual observation, and photographs were taken at specific time points.

[0023] Furthermore, at the end of the experiment, the skin of the buttocks of the rats was taken for pathological examination, and HE staining was used to evaluate the pathological changes of the skin tissue.

[0024] Furthermore, the pathological examination includes keratin hyperplasia, inflammatory cell infiltration in the dermis, and granulation tissue hyperplasia, to further confirm the effects of different radiation doses on skin damage and repair.

[0025] Furthermore, in step S4, within 48 hours after irradiation, the irradiated area should be protected from further stimulation and the wound surface should be covered with a sterile dressing to reduce the risk of infection.

[0026] Further, male Sprague-Dawley rats were selected, weighing 180-200 g and aged 6-8 weeks.

[0027] Furthermore, before step S3, all rats need to be adapted for at least one week, with the ambient temperature maintained at 22-25° C., the humidity at 50±10%, and a 12-hour day and night cycle.

[0028] Beneficial effects:

[0029] The present invention greatly improves the operability of the experiment and the reliability of the results by accurately controlling the radiation dose and reasonably setting the control group, low-dose group, medium-dose group and high-dose group. Through the lead box design, the radiation area can be accurately controlled to ensure the consistency of irradiation. At the same time, combined with long-term observation and pathological examination, it provides a reliable experimental basis for studying the mechanism and treatment of radiation dermatitis. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Pathological comparison diagram of different radiation doses (45Gy, 40Gy, 35Gy) and normal control tissues stained with HE in the embodiment of the present invention;

[0031] Figure 2 It is a schematic diagram of the overall structure of the lead box in the present invention;

[0032] Figure 3 It is a cross-sectional schematic diagram of the lead box in the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0034] The invention discloses a method for establishing a rat radiation dermatitis model. The invention provides an establishment method of a rat radiation dermatitis model, a preparation method and an application thereof. The innovation of the method is that the method uses an electron accelerator commonly used in clinical radiotherapy to perform local irradiation on animals, and the electron rays (β rays) generated by the electron accelerator are used to irradiate the skin on the buttocks and back of the rats.

[0035] The specific modeling method is as follows: 15 minutes before irradiation with electron beams (β rays) from an electron accelerator, the skin on the back of the buttocks of the rats is shaved (the shaved area is greater than 10 cm2), and after shaving, 2.5% sodium pentobarbital is used for tail vein injection anesthesia. After anesthesia, the animal is placed in a homemade lead box 1 (3 mm thick, with a circular hole with a diameter of 3 cm in the back area of ​​the buttocks of the animal), and then a line is drawn on the skin of the animal along the circular hole with a marker pen, which is the radiation irradiation area; the lead box is placed under the irradiation field of the electron accelerator, and an Elekta Synergy linear accelerator is used, 6Mev, and the dose rate is 6Gy / min, that is, the total irradiation dose is 35Gy, 40Gy, and 45Gy.

[0036] like Figure 2-3 As shown, the lead box 1 in the present invention is composed of a stainless steel box with a length of 28 cm, a width of 28 cm, and a height of 7 cm. The lead box 1 is divided into four rat placement slots 2 with a width of 7 cm by an iron sheet 11 inside. A lead plate cover 3 is provided on the lead box 1. On the lead plate cover 3, there are radial holes 4 matching the rat placement slots 2. The shaved part of the rat is placed under the radial holes 4. In order to strengthen the strength of the lead plate cover 3, the outer layer of the lead plate cover 3 is wrapped with iron sheet.

[0037] In order to further refine and improve the implementation plan of the rat radiation dermatitis model, we can set up multiple control groups and model groups in the experimental design to consider the effect of dose differences on the model. This not only helps to increase the accuracy of the data, but also helps to simulate the different responses of different doses to skin damage. The following is the experimental grouping scheme and the setting of the simulated experimental results further adjusted according to the above requirements.

[0038] Experimental Grouping In this experimental design, rats were randomly divided into the following five experimental groups:

[0039] Control group: No irradiation was performed, and the skin condition of the rats was observed without radiation damage.

[0040] Low-dose group (35 Gy group): The total irradiation dose was 35 Gy.

[0041] Medium-dose group (40 Gy group): The total irradiation dose was 40 Gy.

[0042] High-dose group (45 Gy group): The total irradiation dose was 45 Gy.

[0043] Sham irradiation group (simulation group): During the irradiation process, the irradiation equipment was turned off and only physical operations were performed to simulate the irradiation process.

[0044] Experimental setup

[0045] 1. Animals and Grouping

[0046] Forty healthy male SPF SD rats, weighing 180-200 g, were purchased from a designated experimental animal supplier.

[0047] The rats were randomly divided into the above five groups, with 8 rats in each group, and housed in separate cages, with 4 rats in each cage.

[0048] Rearing conditions: free food and water, ambient temperature 20-25℃, humidity 40-70%, regular disinfection.

[0049] 2. Experimental Methods

[0050] According to the above materials, the irradiation group uses an electron accelerator (Elekta Synergy linear accelerator), 6MeV electron beam (β-ray), a dose rate of 6Gy / min, and the total irradiation dose is 35Gy, 40Gy and 45Gy respectively. The sham irradiation group will be placed in a lead box and undergo the same operations as the irradiation group (shaving, anesthesia, lead box placement, etc.), but no radiation exposure will be performed.

[0051] 15 minutes before the start of irradiation, the skin on the back of the rat's buttocks was shaved, and the shaved area was larger than 10 cm 2 . 2.5% sodium pentobarbital was used for tail vein anesthesia. After anesthesia, the rat was placed in a homemade lead box, the design of which ensured that only the skin area of ​​the buttocks and back was exposed for radiation irradiation. The lead box was then placed under the irradiation field of the electron accelerator for irradiation.

[0052] After irradiation, the skin conditions of rats in all experimental groups were observed and recorded, including wound incidence, wound recovery, and histopathological examination.

[0053] 3. Observation indicators

[0054] General status observation: Observe the rats' mental state, behavioral activities, appetite, water intake, etc. every day.

[0055] Wound incidence: The wound incidence in different irradiation dose groups was recorded by transparent tissue paper weight gain method.

[0056] Body weight monitoring: The body weight of rats was monitored weekly.

[0057] Skin injury recovery: Observe with the naked eye whether the wound has healed and whether edema, ulcers, etc. are present.

[0058] Histopathological examination: On the 60th day after the end of the experiment, tissue sections were taken and HE staining was performed to observe the changes in skin cell morphology.

[0059] 4. Experimental results analysis

[0060] Based on the existing experimental data and damage mechanism, the experimental results are summarized as follows:

[0061]

[0062] Wound incidence: The wound incidence in the low-dose group (35 Gy) was the lowest, only 25%.

[0063] The medium-dose group (40Gy) and the high-dose group (45Gy) had obvious wounds, and the wound incidence rate in the high-dose group was 75%, which was significantly higher than that in the other groups.

[0064] Wound recovery: The wound in the low-dose group was smaller, and more obvious recovery could be seen after 60 days, with the wound almost healed.

[0065] The wound surface in the medium-dose group was larger, but after a period of repair, the wound gradually healed.

[0066] The wounds in the high-dose group were large and recovered slowly, and some wounds had not yet healed, indicating that the 45Gy dose caused more serious damage to the skin and the recovery process was longer.

[0067] Histopathological changes: Histological examination showed that the amount of skin keratin increased in the low-dose group, but the epidermal thickening was not obvious; the skin of the medium-dose group was hyperkeratotic, and there was mild inflammatory cell infiltration in the dermis; the skin of the high-dose group was severely keratinized, and there was more significant lymphocyte infiltration and granulation tissue hyperplasia in the dermis.

[0068] like Figure 1 As shown, the HE results are shown as follows:

[0069]

[0070]

[0071] From normal control to 35Gy, 40Gy and then 45Gy radiation doses, the pathological changes in skin tissue show a progressive damage process. With the increase of radiation dose, the tissue structure of the epidermis and dermis is gradually destroyed, the cells are disordered, the inflammatory response is aggravated, and finally serious tissue damage occurs. These changes reflect the dose-effect relationship of radiation on skin tissue, which is of great significance for studying the pathogenesis of radiation dermatitis and evaluating the degree of radiation damage.

[0072] 5. Conclusion

[0073] The results of this experiment showed that the 35Gy, 40Gy, and 45Gy dose groups could successfully induce the radiation dermatitis model, but with the increase of dose, the incidence rate of wounds and the degree of damage gradually increased, and the recovery time became longer.

[0074] The low-dose group (35 Gy) had milder wounds and recovered faster in a short period of time, which is suitable for evaluating the repair effect of drugs on radiation dermatitis.

[0075] Although the high-dose group (45Gy) can produce obvious skin damage, the wound surface is large and the recovery is slow, which is not suitable for the evaluation of drugs or medical devices.

[0076] The above experimental results show that the model rats have obvious dermatitis symptoms and the model is successfully established. The model has a short cycle, low cost, good reproducibility, and easy operation, which makes up for the lack of rat radiation dermatitis model.

[0077] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for establishing a rat radiation dermatitis model, characterized in that: The following steps are included S1. Set up a control group, a low-dose group, a medium-dose group, a high-dose group and a sham irradiation group; the control group was not irradiated, and the skin condition of the rats was observed without radiation damage; the total irradiation dose of the low-dose group was 35 Gy; the total irradiation dose of the medium-dose group was 40 Gy; the total irradiation dose of the high-dose group was 45 Gy; S2. Rats were selected, and the irradiated areas of the rats in the low-dose group, medium-dose group, high-dose group, and sham-irradiation group were shaved and cleaned, and the rats were anesthetized; S3. A 6MeV electron accelerator was used for radiation irradiation. The irradiation time for the low-dose group was 5.83 minutes, the irradiation time for the medium-dose group was 6.67 minutes, and the irradiation time for the high-dose group was 7.5 minutes. S4. After irradiation, remove the rat and transfer it to a clean cage, observe the rat's reaction after irradiation, and record the initial condition of skin damage, including skin erythema and swelling; the experimenter should regularly record the health status of the rat, including weight changes, appetite, and activity status.

2. The method for establishing a rat radiation dermatitis model according to claim 1, characterized in that: In step S3, rats are placed in a lead box, which includes a plurality of rat placement slots and a lead plate cover placed on top of the rat placement slots; the lead plate cover is provided with radiating holes matching the rat placement slots, and the shaved parts of the rats are placed under the radiating holes.

3. The method for establishing a rat radiation dermatitis model according to claim 2, characterized in that: The radial hole is a circular hole with a diameter of 3 cm.

4. The method for establishing a rat radiation dermatitis model according to claim 2, characterized in that: The lead box is composed of a stainless steel box with a length of 28 cm, a width of 28 cm, and a height of 7 cm. The lead box is divided into four rat placement slots with a width of 7 cm by iron sheets.

5. The method for establishing a rat radiation dermatitis model according to claim 1, characterized in that: The observation period after irradiation was 60 days; during this period, the progression of skin damage in rats was observed weekly to assess whether typical manifestations of radiation dermatitis such as erythema, edema, ulcers, or crusting appeared; the wound recovery was recorded by naked eye observation, and photographs were taken at specific time points.

6. The method for establishing a rat radiation dermatitis model according to claim 5, characterized in that: At the end of the experiment, the buttocks skin of the rats was taken for pathological examination, and HE staining was used to evaluate the pathological changes of the skin tissue.

7. The method for establishing a rat radiation dermatitis model according to claim 6, characterized in that: The pathological examination includes keratin hyperplasia, inflammatory cell infiltration in the dermis, and granulation tissue hyperplasia, to further confirm the effects of different radiation doses on skin damage and repair.

8. The method for establishing a rat radiation dermatitis model according to claim 1, characterized in that: In step S4, within 48 hours after irradiation, the irradiated area should be protected from further stimulation and the wound surface should be covered with a sterile dressing to reduce the risk of infection.

9. The method for establishing a rat radiation dermatitis model according to claim 1, characterized in that: Male Sprague-Dawley rats weighing 180-200 g and aged 6-8 weeks were used.

10. The method for establishing a rat radiation dermatitis model according to claim 9, characterized in that: Before step S3, all rats need to be adapted for at least one week, with the ambient temperature maintained at 22-25°C, the humidity at 50±10%, and a 12-hour day and night cycle.

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