Hydrogel as well as preparation method and application thereof

Abstract

The invention relates to the technical field of biomedical materials, in particular to hydrogel as well as a preparation method and application thereof. The hydrogel is obtained by crosslinking a polymer framework material, a functional additive and a shielding agent, the polymer framework material comprises any one or more of gelatin, carboxymethyl chitosan, hyaluronic acid, chitosan, collagen, polyvinyl alcohol, sodium carboxymethyl cellulose and sodium alginate; the functional additive comprises any one or more of tannic acid, tea polyphenol, vitamin C and procyanidine; the shielding agent comprises any one or more of barium sulfate, bismuth simple substance and bismuth-containing compound. The hydrogel provided by the invention can effectively isolate radiotherapy rays, reduce oxidative stress reaction, provide a protective barrier for normal tissues in a radiotherapy process and reduce radiation damage, has excellent tissue repair promotion capability, is safe in components, fast in metabolism and adjustable in flowability and adhesion, and is more beneficial to adaptation in rectum or skin tissues.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical materials, and in particular to a hydrogel and a preparation method and application thereof. Background Art

[0002] The global incidence of cancer is increasing significantly, projected to reach approximately 26 million new cases by 2030, up from approximately 9 million in 2017. Against this backdrop, radiotherapy, as the single most effective non-surgical treatment for cancer, has become increasingly important. Approximately 7 million patients require radiotherapy annually. Although radiotherapy accounts for only 5% of total cancer care expenditures, it is a key component of the treatment plan for nearly 40% of patients and successfully cures approximately 16% of cancer cases. Approximately 30% to 50% of all cancer patients receive radiotherapy, either alone or in combination with chemotherapy and surgery. However, as cure rates for malignant tumors increase, a growing number of long-term survivors may face various chronic conditions. Therefore, a thorough understanding and understanding of the common side effects of radiotherapy is crucial to ensure that patients receive the best possible treatment outcomes and quality of life.

[0003] Radiation therapy (RT) mainly uses focused high-energy radiation to destroy the genetic material DNA of tumor cells, causing them to lose their regenerative ability, thereby achieving the purpose of killing tumor cells. However, while treating tumors, radiotherapy will also produce adverse reactions on surrounding normal tissues and cells. These reactions can be divided into two categories: systemic reactions and local damage. Systemic reactions mainly include symptoms such as fatigue, decreased appetite, nausea and vomiting, decreased white blood cell count, slow reaction and insomnia. These symptoms usually gradually improve after the end of radiotherapy. Local damage refers to the damage caused by radiotherapy to normal tissues around the tumor, which may involve multiple parts such as skin, mucous membranes, salivary glands, heart, lungs, esophagus, liver, gastrointestinal tract, urinary system and bones.

[0004] To minimize radiation damage to normal tissues, radiation protection primarily addresses physical and chemical barriers. Physical protection minimizes the radiation dose to normal tissues by optimizing radiation therapy techniques, adjusting radiation doses, and using protective equipment. Chemical protection, on the other hand, involves the use of drugs or biologics to mitigate adverse reactions and protect normal tissues. Currently, prostate cancer radiation protection hydrogels that have received EU CE certification and US FDA 510(k) clearance include SpaceOAR and Barrigel. These absorbable materials solidify in situ after injection, creating a temporary physical barrier between the prostate and the rectum, thereby reducing the radiation dose to the rectum during radiation therapy and lowering the risk of complications such as radiation proctitis. For example, SpaceOAR hydrogel is a physical barrier that solidifies after injection, temporarily shielding the rectum from high-dose radiation, thereby reducing the amount of radiation received and lowering the incidence of enterotoxicity. The hydrogel lasts for three months after a single injection and is gradually absorbed by the body within six months. Clinical data show that the use of this hydrogel can effectively reduce the radiation dose received by the rectum, reduce rectal pain, and alleviate long-term complications. However, SpaceOAR hydrogel also has some limitations. First, it mainly reduces proctitis caused by radiotherapy through physical protection, but its reactive oxygen species scavenging, anti-inflammatory effects, and tissue damage repair functions still need to be improved. Secondly, the high cost may limit its use in patients with limited financial conditions. In addition, its applicability is also limited by factors such as radiotherapy dose, time, and tumor location. Finally, the gel may cause side effects and complications such as infection, bleeding, and pain, and the technical difficulty of the surgical implantation process may also increase the risk.

[0005] Therefore, there is an urgent need to develop a new multifunctional radiotherapy protective hydrogel. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a hydrogel and its preparation method and application. The hydrogel provided by the present invention can effectively isolate radiotherapy rays, reduce oxidative stress response, provide a protective barrier for normal tissues during radiotherapy, reduce radiation damage, and at the same time has excellent ability to promote tissue repair. The ingredients are safe, the metabolism is fast, the fluidity and adhesion are adjustable, and it is more conducive to adaptation in rectal or skin tissue.

[0007] In a first aspect, the present invention provides a hydrogel obtained by cross-linking a polymer skeleton material, a functional additive, and a shielding agent;

[0008] The polymer skeleton material includes any one or more of gelatin, carboxymethyl chitosan, hyaluronic acid, chitosan, collagen, polyvinyl alcohol, sodium carboxymethyl cellulose and sodium alginate;

[0009] The functional additives include any one or more of tannic acid, tea polyphenols, vitamin C and proanthocyanidins;

[0010] The shielding agent includes any one or more of barium sulfate, bismuth element and bismuth-containing compound.

[0011] The hydrogel provided by the present invention can effectively isolate radiotherapy rays, reduce oxidative stress reactions, provide a protective barrier for normal tissues during radiotherapy, reduce radiation damage, and has excellent tissue repair promoting ability. In addition, the hydrogel is safe in composition, rapidly metabolized, and has adjustable fluidity and adhesion, making it more suitable for adaptation in rectal or skin tissues. Specifically:

[0012] The hydrogel provided by the present invention is obtained by cross-linking a polymer skeleton material, a functional additive and a shielding agent, wherein the polymer skeleton material has good gelling properties, biocompatibility, degradability and hydrophilicity, etc.; the functional additive is based on its phenolic structure, has excellent antioxidant properties, can remove a variety of free radicals, and inhibit oxidase activity, thereby maintaining intracellular redox balance, reducing the occurrence of oxidative reactions, while having excellent properties such as biocompatibility, degradability, mild reaction conditions, and diverse functions, as a cross-linking agent, a functional enhancer and an active ingredient, interacting with the polymer skeleton material through reversible ionic bonds and hydrogen bonds to form a stable three-dimensional network structure, the hydrogel obtained not only has antioxidant properties, but also possesses certain adhesion, which helps to enhance the staying ability of the shielding agent in the body. The shielding agent has high density, high atomic number and excellent radiation absorption capacity, can effectively absorb and scatter X-rays and gamma rays, reduce the damage of radiation to surrounding tissues and organs, and the introduction of the shielding agent can achieve the effect of hydrogel isolating radiotherapy rays. Therefore, the hydrogel provided by the present invention can play multiple roles after being injected into the target area, such as isolating radiotherapy rays, reducing oxidative stress, and promoting tissue repair. In addition, the hydrogel components of the present invention are safe and metabolized quickly. By adjusting the composition of the hydrogel system, the fluidity and adhesion of the hydrogel can be changed, making it more conducive to adapting to rectal or skin tissue, overcoming the defects of existing hydrogels such as high cost, limited applicability, lack of antioxidant capacity, and the possibility of causing side effects and complications.

[0013] In some embodiments of the present invention, the hydrogel is formed by cross-linking chitosan, tannic acid, and barium sulfate. Chitosan and tannic acid form the hydrogel through reversible ionic and hydrogen bonding, while the introduction of barium sulfate enhances the radiotherapy protection effect. By adjusting the ratio of these three materials, a multifunctional radiotherapy protection hydrogel with a certain degree of adhesion and fluidity can be obtained.

[0014] The polymer skeleton material in the hydrogel provided by the present invention can include multiple components that work synergistically, which can bring better effects, effectively improve the performance of the hydrogel, meet more complex application requirements, and achieve more efficient and safer treatment effects.

[0015] In some embodiments of the present invention, the polymer skeleton material is selected from a combination of gelatin and hyaluronic acid, wherein gelatin provides mechanical support and a stable network structure, while hyaluronic acid enhances moisture retention and lubricity while promoting cell adhesion and proliferation. The combination of the two can not only provide stable mechanical properties, but also significantly improve the biocompatibility and cell behavior of the hydrogel.

[0016] In some embodiments of the present invention, the polymer skeleton material is selected from a combination of chitosan and sodium alginate, wherein chitosan has antibacterial and repair-promoting effects, while sodium alginate has good gelling properties and biocompatibility. Through ionic crosslinking, the two form a stable hydrogel with both antibacterial and mechanical strength.

[0017] In some embodiments of the present invention, the polymer skeleton material is selected from a combination of collagen and polyvinyl alcohol, wherein collagen provides cell adhesion sites and biological activity, while polyvinyl alcohol enhances the mechanical strength and stability of the material. The combination of the two can both simulate the extracellular matrix environment and improve the durability of the material.

[0018] As a preferred technical solution of the present invention, the mass ratio of the polymer skeleton material, functional additive and shielding agent is (45-160):(12-42):(10-30), for example, 45:12:10, 80:20:15, 120:30:20, 160:42:30, 150:15:15, etc.

[0019] In a second aspect, the present invention provides a method for preparing the hydrogel as described in the first aspect, the preparation method comprising: placing a polymer skeleton material, a functional additive, and a shielding agent in solvent water for reaction to obtain the hydrogel.

[0020] The solvent water described in the present invention is ultrapure water, such as deionized water.

[0021] As a preferred technical solution of the present invention, the preparation method comprises: dispersing the shielding agent in an aqueous solution of a polymer skeleton material, adding dropwise an aqueous solution of a functional additive to react, and obtaining the hydrogel.

[0022] As a preferred technical solution of the present invention, the ratio of the total mass of the polymer skeleton material, functional additives and shielding agent to the volume of the solvent water is 67-232 mg:1.8-2.6 mL, for example, 67 mg:1.8 mL, 100 mg:1.9 mL, 125 mg:2.0 mL, 150 mg:2.1 mL, 175 mg:2.3 mL, 200 mg:2.5 mL, 232 mg:2.6 mL, etc.

[0023] As a preferred technical solution of the present invention, the reaction is carried out under stirring.

[0024] As a preferred technical solution of the present invention, the reaction time is 2-10 min, for example, 2 min, 4 min, 6 min, 8 min, 10 min, etc.

[0025] In a third aspect, the present invention provides use of the hydrogel described in the first aspect or the hydrogel prepared by the preparation method described in the second aspect in radiotherapy protection.

[0026] The technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:

[0027] The hydrogel provided by the present invention can effectively isolate radiotherapy rays, reduce oxidative stress reactions, provide a protective barrier for normal tissues during radiotherapy, reduce radiation damage, and at the same time has excellent ability to promote tissue repair. In addition, the ingredients are safe, the metabolism is fast, and the fluidity and adhesion are adjustable, which is more conducive to adaptation in rectal or skin tissues. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] Figure 1 The results of the scavenging ability of the hydrogels prepared in Examples 1-3 and Comparative Example 1 on ABTS free radicals;

[0031] Figure 2 The cell survival rate results of mouse L929 fibroblasts at different hydrogel extract concentrations;

[0032] Figure 3The blood compatibility results of mouse red blood cells at different hydrogel extract concentrations;

[0033] Figure 4 This is a fluorescence image of the hydrogel's retention in the rat intestine;

[0034] Figure 5 Fluorescence quantification results of hydrogel retention in rat intestine;

[0035] Figure 6 The results of colonoscopy, HE staining and AB-PAS staining of rats in different groups in the rat radiation proctitis model are shown;

[0036] Figure 7 These are photos of the skin appearance, HE staining, and Masson staining results of mice in different groups after radiotherapy in the mouse radiation dermatitis model;

[0037] Figure 8 HE staining results of various organs, colonoscopy results, skin images, and HE staining results of modeling sites of rats in the rectum group and mice in the skin group after treatment with hydrogel;

[0038] Figure 9 These are the organ index results after hydrogel injection into the rat intestine;

[0039] Figure 10 These are the organ index results after applying the hydrogel on the mouse skin surface;

[0040] Figure 11 These are the blood biochemical results after hydrogel injection into the intestine of rats;

[0041] Figure 12 Blood biochemical results after applying hydrogel on mouse skin surface;

[0042] Figure 13 These are the blood routine results after hydrogel injection into the intestine of rats;

[0043] Figure 14 These are the blood routine results after applying the hydrogel on the mouse skin surface. DETAILED DESCRIPTION

[0044] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0045] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0046] Example 1

[0047] This embodiment provides a hydrogel and a preparation method thereof, wherein the preparation method comprises the following steps:

[0048] (1) 3 g of carboxymethyl chitosan was dissolved in 100 mL of deionized water to obtain a 3% carboxymethyl chitosan solution, which was set aside; 6 g of tannic acid was dissolved in 100 mL of deionized water to obtain a 6% tannic acid solution, which was set aside;

[0049] (2) 0.026 g of barium sulfate powder was dispersed in 2 mL of carboxymethyl chitosan solution. Under magnetic stirring, 0.4 mL of tannic acid solution was added dropwise using a syringe and reacted for 2 minutes to obtain the hydrogel.

[0050] Example 2

[0051] This embodiment provides a hydrogel and a preparation method thereof, wherein the preparation method comprises the following steps:

[0052] (1) Dissolve 7 g of gelatin in 100 mL of deionized water to obtain a 7% gelatin solution, which is set aside; dissolve 6 g of tea polyphenols in 100 mL of deionized water to obtain a 6% tea polyphenols solution, which is set aside;

[0053] (2) 0.04 g of bismuth powder was dispersed in 1.8 mL of gelatin solution. Under magnetic stirring, 0.6 mL of tea polyphenol solution was added dropwise using a syringe and reacted for 3 minutes to obtain the hydrogel.

[0054] Example 3

[0055] This embodiment provides a hydrogel and a preparation method thereof, wherein the preparation method comprises the following steps:

[0056] (1) Take 5 g of sodium alginate and dissolve it in 100 mL of deionized water to obtain a 5% sodium alginate solution, which is set aside; take 4 g of proanthocyanidin and dissolve it in 100 mL of deionized water to obtain a 4% proanthocyanidin solution, which is set aside;

[0057] (2) 0.05 g of barium sulfate powder was dispersed in 1.5 mL of sodium alginate solution. Under magnetic stirring, 0.5 mL of proanthocyanidin solution was added dropwise using a syringe and reacted for 4 minutes to obtain the hydrogel.

[0058] Examples 4-5

[0059] This embodiment provides a hydrogel and a preparation method thereof. The preparation method is the same as that of Example 1, except that the amounts of barium sulfate powder used are 0.5 g (Example 4) and 0.005 g (Example 5), respectively.

[0060] Comparative Example 1

[0061] This comparative example provides a hydrogel and a preparation method thereof, wherein the preparation method comprises the following steps:

[0062] (1) 3 g of carboxymethyl chitosan was dissolved in 100 mL of deionized water to obtain a 3% carboxymethyl chitosan solution, which was set aside; 6 g of tannic acid was dissolved in 100 mL of deionized water to obtain a 6% tannic acid solution, which was set aside;

[0063] (2) 2 mL of carboxymethyl chitosan solution was taken, and 0.4 mL of tannic acid solution was added dropwise using a syringe under magnetic stirring, and the reaction was carried out for 2 minutes to obtain the hydrogel.

[0064] Performance Test 1

[0065] The hydrogel of the present invention was tested for its in vitro antioxidant properties.

[0066] 1.2 g of the hydrogels prepared in Examples 1-3 and Comparative Example 1 were added to 6 mL of PBS and incubated on a shaker at 37°C for 24 hours to obtain a 200 mg / mL extract. The extracts were then diluted with PBS to obtain hydrogel extracts with concentrations of 5 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, 30 mg / mL, and 40 mg / mL, respectively.

[0067] The total antioxidant capacity test kit (ABTS method) was used to test the ability of the hydrogel to scavenge ABTS free radicals. Figure 1 As shown, Figure 1 The results of the scavenging ability of the hydrogels prepared in Examples 1-3 and Comparative Example 1 on ABTS free radicals are shown. Figure 1 It can be found that when the concentration of the hydrogel extract reaches above 15 mg / mL, it exhibits good scavenging ability for ABTS free radicals, that is, it has a significant effect of scavenging reactive oxygen species.

[0068] Performance Test 2

[0069] The biosafety of the hydrogel was tested in vitro.

[0070] 2.1 The cell viability was detected by exposure to hydrogel extracts of different concentrations. Mouse L929 fibroblasts were selected to evaluate the cell compatibility of the hydrogel prepared in Example 1 using the MTT method. A sample group, a blank control group, and a negative control group were set up.

[0071] The specific test steps for the sample group are as follows:

[0072] (1) Take 1.2 g of hydrogel, add 6 mL of DMEM complete medium, and incubate in a shaker at 37°C for 24 h to obtain a 200 mg / mL extract. Use DMEM complete medium to dilute the extract to 10 mg / mL, 20 mg / mL, 40 mg / mL, 60 mg / mL, 80 mg / mL, and 100 mg / mL hydrogel extracts, respectively.

[0073] (2) Cell counting: 5000 cells were plated in each well of a 96-well plate, with 100 μL of DMEM complete medium added. The cells were incubated in a cell culture incubator for 24 h to allow them to adhere to the wall. The edge wells were filled with 200 μL of sterile PBS.

[0074] (3) After adhesion, without aspirating the culture medium, 100 μL of the hydrogel extract of different concentrations prepared in step (1) was added to different wells and cultured for 24 h (the concentration of the hydrogel extract was diluted 1 times after addition).

[0075] (4) Aspirate the supernatant and wash 2-3 times with PBS.

[0076] (5) Add 100 μL of complete culture medium and 20 μL of MTT (5 mg / mL, i.e., 0.5% MTT) solution to each well and incubate at 37°C for 4 h.

[0077] (6) Remove the culture medium and add 200 μL of DMSO to each well. Incubate at 37°C in the dark for 10 min to allow the crystals to fully dissolve.

[0078] The experimental steps of the blank control group were the same as those of the sample group, except that in step (2) of the blank control group, each well contained only 100 μL of DMEM complete medium without cells, and in step (3), 100 μL of the hydrogel extracts of different concentrations prepared in step (1) were replaced with 100 μL of DMEM complete medium.

[0079] The experimental steps of the negative control group were the same as those of the sample group, except that in step (3) of the negative control group, 100 μL of the hydrogel extracts of different concentrations prepared in step (1) was replaced with 100 μL of DMEM complete culture medium.

[0080] The absorbance C of the solution obtained in step (6) at 570 nm was measured using a multifunctional microplate reader. The cell survival rate was calculated according to the following formula:

[0081] Cell survival rate (%) = (C 样本 -C 空白对照组 ) / (C 阴性对照组 -C 空白对照组 )×100%

[0082] Figure 2The cell survival rate of mouse L929 fibroblasts at different hydrogel extract concentrations. Figure 2 It can be found that compared with the control group, when the concentration of the hydrogel extract is 5-50 mg / mL, the cell survival rate is greater than 80%, indicating that the hydrogel provided by the present invention has good cell compatibility.

[0083] 2.2 The hemocompatibility of the hydrogel prepared in Example 1 was evaluated by testing the hemolysis of cells exposed to hydrogel extracts of different concentrations using mouse red blood cells. The specific steps were as follows:

[0084] (1) Take 1.2 g of hydrogel, add 6 mL of PBS, and incubate in a shaker at 37°C for 24 h to obtain a 200 mg / mL extract. Use PBS to dilute the extract to 20 mg / mL, 40 mg / mL, 60 mg / mL, 80 mg / mL, and 100 mg / mL hydrogel extracts, respectively. Use PBS as the control group, i.e., the hydrogel extract concentration is 0 mg / mL.

[0085] (2) After the mice were anesthetized, the abdominal cavity was opened to collect blood from the heart. Whole blood was collected using a blood collection tube containing sodium heparin. After centrifugation at 2000 rpm for 5 minutes, the supernatant was discarded and PBS was slowly added along the tube wall to wash the blood cells three times.

[0086] (3) After the third centrifugation, the supernatant was discarded, the red blood cell volume was recorded, and the red blood cell suspension was diluted to 5% with PBS. 0.5 mL of hydrogel extracts of different concentrations (20 mg / mL, 40 mg / mL, 60 mg / mL, 80 mg / mL, 100 mg / mL) was mixed with equal volumes of the 5% red blood cell suspension and incubated in a 37°C constant temperature shaker for 1 h.

[0087] (4) After centrifugation of the mixture, the supernatant was discarded and the red blood cells in the bottom layer after centrifugation were resuspended with PBS. The red blood cell morphology was observed under an optical microscope. 0.5 mL of PBS was added to the negative control group and 0.5 mL of 1% Triton X-100 was added to the positive control group. Each group was repeated three times.

[0088] Figure 3 The blood compatibility results of mouse red blood cells at different hydrogel extract concentrations. Figure 3 It can be found that when the concentration of the hydrogel extract reaches 100 mg / mL, the red blood cells are evenly distributed without aggregation and the morphological structure does not change, indicating that the hydrogel of the present invention has good blood compatibility.

[0089] Performance Test 3

[0090] Intestinal retention test: The retention of the hydrogel of the present invention in the rat intestine was observed using a small animal imaging device.

[0091] The rats were anesthetized and then enema was performed. The gel group was enemaed with 2 mL of the hydrogel prepared in Example 1 + 0.1 mL of ICG aqueous solution, and the free ICG group was enemaed with 2 mL of ICG aqueous solution.

[0092] The results are as follows Figure 4 and Figure 5 As shown, Figure 4 This is a fluorescence image of the hydrogel's retention in the rat intestine. Figure 5 The fluorescence quantitative results of the hydrogel retention in the rat intestine. Figure 4 and Figure 5 It was found that within 6 hours of enema administration, the hydrogel had a good retention effect in the intestines and could cover the rectum. After 24 hours of enema administration, the hydrogel was essentially cleared from the intestines. The hydrogel in the intestines was eliminated within one day, and there were no cumulative gastrointestinal effects. Within 24 hours, there was no leakage of the gel and potential damage to other organs, indicating that the hydrogel composition provided by the present invention is safe, metabolized rapidly, and has suitable fluidity and adhesion.

[0093] Performance Test 4

[0094] Detect the radiotherapy protection effect of hydrogel.

[0095] (1) Establishment of a rat radiation proctitis model

[0096] All SD rats were randomly divided into 5 groups:

[0097] Normal group: enema 2 mL of normal saline;

[0098] Radiotherapy group: enema 2 mL normal saline;

[0099] Gel control group: enema 2 mL of the hydrogel prepared in Comparative Example 1, once;

[0100] Gel once group: 2 mL of the hydrogel prepared in Example 1 was administered enema once;

[0101] Gel three times group: enema 2 mL of the hydrogel prepared in Example 1, once;

[0102] There were 5 rats in each group. Except for the normal group, the other groups received radiotherapy after enema.

[0103] After complete muscle relaxation, the SD rats in each group were fixed in the supine position on a surgical board and irradiated with a 6MV (radiation energy) X-ray linear accelerator to the lower abdomen (from the pubic symphysis to the anus). The irradiation area was 4 cm × 3 cm, and the remaining area was shielded with thick lead plates. The source-skin distance (the distance from the radiation source along the central axis of the radiation to the body membrane surface) was 100 cm. The irradiation dose was 25 Gy at a dose rate of 400 cGy / min for 6 minutes and 15 seconds. This established a radiation proctitis model.

[0104] The three-times gel group was given an enema of the hydrogel prepared in Example 1 after radiotherapy, once every 10 days, 2 mL each time, for a total of 3 times.

[0105] The rats were killed 40 days after radiotherapy, and the rectal tissues were collected and fixed in 4% paraformaldehyde solution, and then stained with HE and AB-PAS.

[0106] Figure 6 The colonoscopy, HE staining and AB-PAS staining results of different groups of rats in the rat radiation proctitis model, from left to right, are the colonoscopy results on the 10th day after radiotherapy, the colonoscopy results on the 20th day, the colonoscopy results on the 30th day, the colonoscopy results on the 40th day, the HE staining results of the rectal tissue on the 40th day, and the AB-PAS staining results of the rectal tissue on the 40th day. Figure 6 The results of colonoscopy and HE staining showed that the radiotherapy group and the gel control group had mucosal necrosis, inflammatory cell infiltration, and slight damage to the intestinal glands; while the gel once group and the gel three times group were similar to the normal group, indicating that the hydrogel of the present invention has an excellent protective effect. It can be seen from the AB-PAS results that the hydrogel of the present invention reduces the damage of radiotherapy to normal tissues, retains the crypt structure and most goblet cells, and reduces the abnormal secretion of mucus. In short, the hydrogel provided by the present invention can effectively isolate radiotherapy rays, provide a protective barrier for normal tissues during radiotherapy, reduce radiation damage, and effectively promote tissue repair after radiotherapy.

[0107] (2) Establishment of a mouse radiation dermatitis model

[0108] ICR mice after hind limb hair removal were randomly divided into 5 groups:

[0109] Normal group: no treatment;

[0110] Radiotherapy group: no smear treatment;

[0111] Biafine group: Biafine was applied to the hind limbs;

[0112] Gel group: the hydrogel prepared in Example 1 was applied to the hind limbs;

[0113] Gel control group: the hydrogel prepared in Comparative Example 1 was applied to the hind limbs;

[0114] There were 5 rats in each group. Except for the normal group, the other groups were treated with radiotherapy after applying the drug.

[0115] After the muscles were completely relaxed, each group of ICR mice was fixed on the operating board in a prone position and the hind limb skin was irradiated with 6MeV (radiation energy) electron beams. The rest of the body was shielded with thick lead plates. The source-skin distance (the distance from the radiation source along the central axis of the radiation to the body membrane surface) was 100 cm. The irradiation dose was 40 Gy, the dose rate was 500 cGy / min, and the irradiation time was 8 min.

[0116] The mice were killed 30 days after radiotherapy, and the skin tissues were collected and fixed in 4% paraformaldehyde solution, and then stained with HE and Masson staining.

[0117] Figure 7 These are the photos of the skin appearance, HE staining, and Masson staining results of mice in different groups after radiotherapy in the mouse radiation dermatitis model. From left to right, each column shows the photos of the skin appearance on the 3rd, 12th, 21st, and 30th days after radiotherapy, the HE staining results of the skin tissue on the 30th day, and the Masson staining results of the skin tissue on the 30th day.

[0118] Depend on Figure 7 The HE section results showed that compared with the normal group, the radiotherapy group had epidermal hyperplasia, partial epidermal loss, and reduced skin glands; while the gel group had less epidermal hyperplasia and still had skin glands and hair follicles; compared with the radiotherapy group and the Biafine group, the gel control group had less epidermal hyperplasia, but still had more epidermal hyperplasia than the gel group. The Masson staining results showed that compared with the other groups, the skin structure of the gel group was more complete, the formation of skin appendages (such as hair follicles and sweat glands) increased, and inflammatory infiltration was reduced. Compared with the Biafine group and the gel control group, the gel group showed excellent skin tissue regeneration ability. The epidermis of the radiotherapy group was thickened and partially defective, and excessive collagen fiber deposition and binding during the remodeling stage would lead to pathological scar formation, while the collagen fibers in the dermis of the gel group were arranged in a continuous and orderly manner, promoting scarless healing. Overall, the hydrogel in the gel group accelerated the healing of skin wounds, promoted the regeneration of dermal appendages, and made the skin have characteristics closer to healthy tissue, indicating that the hydrogel provided by the present invention has excellent radiotherapy protection and treatment effects as well as excellent ability to promote tissue repair.

[0119] Performance Test 5

[0120] The in vivo biocompatibility of the hydrogel was tested.

[0121] (1) Rectal group: The hydrogel prepared in Example 1 or normal saline was injected into the intestines of SD rats by enema, and then daily clinical manifestations were observed, including:

[0122] Gel group: 2 mL of hydrogel enema every 3 days, 4 times;

[0123] Normal group: 2 mL of normal saline was administered enema 4 times every 3 days.

[0124] (2) Skin group: After hair removal on the left leg of ICR mice, the hydrogel prepared in Example 1 was applied to the skin surface of the left leg, and then daily clinical manifestations were observed, including:

[0125] Gel group: After hair removal, apply 0.5 mL of hydrogel every day for 7 consecutive days;

[0126] Normal group: no treatment was performed after hair removal.

[0127] (3) Rats were painlessly killed from the first enema to the 30th day, and mice were painlessly killed from the first application of hydrogel to the 30th day. Apical blood and key organs such as heart, liver, spleen, lung, and kidney were collected from rats in the rectum group (gel group and normal group) and mice in the skin group (gel group and normal group), and then HE staining was performed on each tissue to detect its histopathological characteristics.

[0128] In addition, test kits were used to measure serum levels of organ damage markers, such as creatinine (CRE), blood urea nitrogen (BUN), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). Routine blood tests were also performed on rats and mice, including measurements of changes in hemoglobin concentration, red blood cell count, total white blood cell count, and platelet count.

[0129] The results are as follows Figure 8-14 As shown, Figure 8 HE staining results of various organs, colonoscopy results, skin pictures and HE staining results of modeling sites of rats in the rectum group and mice in the skin group after being treated with hydrogel. Figure 9 These are the organ index results after hydrogel injection into the rat intestine. Figure 10 This is the organ index result after applying hydrogel on the mouse skin surface. Figure 11 These are the blood biochemical results after hydrogel injection into the rat intestine. Figure 12 The blood biochemical results after applying hydrogel on the mouse skin surface. Figure 13 These are the blood routine results after hydrogel injection into the rat intestine. Figure 14 These are the blood routine results after applying the hydrogel on the mouse skin surface.

[0130] From the organ indexes, blood biochemistry, blood routine tests and HE sections of important organs of rats and mice in the figure, it can be found that there is no significant difference between the gel group and the normal group, indicating that the hydrogel provided by the present invention has good biosafety.

[0131] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0132] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments described herein, but is to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A hydrogel, characterized in that The hydrogel is obtained by cross-linking a polymer skeleton material, a functional additive and a shielding agent; The polymer skeleton material includes any one or more of gelatin, carboxymethyl chitosan, hyaluronic acid, chitosan, collagen, polyvinyl alcohol, sodium carboxymethyl cellulose and sodium alginate; The functional additives include any one or more of tannic acid, tea polyphenols, vitamin C and proanthocyanidins; The shielding agent includes any one or more of barium sulfate, bismuth element and bismuth-containing compound.

2. The hydrogel according to claim 1, wherein The mass ratio of the polymer skeleton material, the functional additive and the shielding agent is (45-160):(12-42):(10-30).

3. A method for preparing the hydrogel according to claim 1 or 2, characterized in that: The preparation method comprises: placing a polymer skeleton material, a functional additive and a shielding agent in solvent water for reaction to obtain the hydrogel.

4. The preparation method according to claim 3, characterized in that The preparation method comprises: dispersing a shielding agent in an aqueous solution of a polymer skeleton material, and dropwise adding an aqueous solution of a functional additive to carry out a reaction to obtain the hydrogel.

5. The preparation method according to claim 3, characterized in that The ratio of the total mass of the polymer skeleton material, the functional additive and the shielding agent to the volume of the solvent water is 67-232 mg:1.8-2.6 mL.

6. The preparation method according to claim 3, characterized in that The reaction is carried out under stirring.

7. The preparation method according to claim 3, characterized in that The reaction time is 2-10 minutes.

8. Use of the hydrogel according to claim 1 or 2 or the hydrogel prepared by the preparation method according to any one of claims 3 to 7 in radiotherapy protection.

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