| 0bjective: Establishing a radiation proctitis in Sprague Dawley(SD) rats model to study whether xiaozhiling, gentamicin, glutamine, mesalazine retention enema prevent and treat acute radiation proctitis to prevent chronic radiation proctitis and explore its mechanism. Methods: 1. Establish radiation proctitis in SD rat model(1) Irradiation method: Establish radiation proctitis in Sprague Dawley rats model by a single large dose 6MV-X ray local irradiation. The 60 female SD rats were randomly divided into 6 groups, 10 rats in each group, the irradiation doses were: 0Gy, 17.5Gy, 20 Gy, 22.5Gy, 25 Gy, 27.5Gy, the rats were anesthetized by intraperitoneal injection of pentobarbital sodium, fixed in supine position, the irradiation range was from the pubic symphysis to the anus, field area was about 3×4cm, source skin distance was 100 cm and the dose rate was 400 c Gy/min.(2)Observation index: animals were observed daily water intake, body weight, food intake, stool and independent spirit activities. 5 rats in each group were killed at 7d, 14 d after irradiation, fixed and embedded in paraffin, HE staining, observed pathological changes of rats rectum tissue under light microscope.(3) Evaluation model: The general condition of rats: food and water intake decreased, emerged loose stools, mucous, bloody stool and othersymptoms. Histopathology of rectum was severe inflammatory changes. 2. Evaluation of curative effect of drug retention enema and the mechanism research:1) Grouping and medication:225 rats were randomly divided into 5 groups: normal control group, negative control group, positive control group, compound enema group 1, compound enema group 2, 45 rats in each group, dealed with not irradiation and normal saline enema, enema of smecta, gentamicin, dexamethasone and irradiation, irradiation and xiaozhiling, gentamicin, glutamine, irradiation and xiaozhiling, gentamicin, glutamine, mesalazine. 2) The observation method and content:(1) Observed daily rats’ general features after irradiation: eating and drinking water, defecation, autonomic activities, perianal hair removal, bleeding, scoring record.(2)1W, 2W, 4W, 6W, 8W, 10 W, 12 W, 14 W, 16 W after irradiation 5 rats in each group were randomly selected to take blood samples, removed after anesthesia,and the rectal tissues were taked and stained with HE to observe the pathological change.(3) Enzyme linked immunosorbent assay(ELISA) was used to test the level of serum in rats of interleukin in serum-6(IL-6), interleukin-8(IL-8), tumor necrosis factor alpha(TNF-α). Reruts: 1. Establish radiation proctitis in SD rat model:(1) Local radiation injuryed rats, impacted general conditions of rats, damage degree was bigger with the increase of irradiation dose, general features and pathological scores were higher.(2)25Gy group was consistent with the performance, pathology was amoderate to severe inflammation, so 25 Gy was selected as the irradiation dose of radiation proctitis model. 2. Evaluation of curative effect of drug retention enema and the mechanism research: 1) According to the experimental pathology results indicated that about 1~4W after irradiation was acute phase, about 5 ~ 11 W after irradiation was sub acute phase, about 12 W after irradiation was the chronic phase. 2) The incidence of acute and chronic radiation proctitis(1)the incidence of acute radiation proctitis of negative control group, positive control group, compound enema 1, compound enema group 2 was respectively 95.56%, 91.11%, 88.89%, 86.67%. drug retention enema did not reduce the incidence of acute radiation proctitis(2)The incidence of chronic radiation proctitis: The the total incidence rates after 12 weeks of negative control group, positive control group, compound enema group 1, compound enema group 2 was respectively 40%, 20%, 13.33%, 6.67%.The incidence of compound enema group 2 had statistical difference compared with the negative control group(P < 0.05), indicated that dug group 2 can effectively reduce the incidence of chronic. 3)The general signs score: the positive control group, compound enema group 1, compound enema group 2 compared with normal control group and negative control group, there was statistically significant(P < 0.01), suggested that drug retention enema could effectively treat acute radiation proctitis, and reduced the symptoms of rats in acute, subacute andchronic phase. The compound enema group 1and 2 compared with the positive control group, there was statistical significance in general(P < 0.05), indicated that the compound enema group 1and 2 preventing and treating radiation proctitis was better than the positive control group. Compound enema group 1and 2 were no significant difference at each time point, but the scores of compound enema group 2 was lower than that of compound enema group 1, indicating that the compound enema group 2 may have better effect. 4) The pathological score: the positive control group, compound enema group 1, compound enema group 2 compared with the normal control group, negative control group, there was statistically significant(P < 0.05), suggested that drug retention enema was effective in the treatment of acute radiation proctitis enema, which can reduce the degree of inflammation, injury and the classification in acute, sub acute, chronic radiation proctitis. The compound enema group 1and 2 compared with the positive control group was statistically significant(P < 0.05), indicated that the compound enema group 1and 2 was better to prevent and treat radiation proctitis. Compound enema group 1and 2 were no significant difference, but the overall score of the compound enema group 2 was lower than compound enema group 1, indicated that the compound enema group 2 may have better effect. 5)The level of serum in rats of IL-6, IL-8, TNF-α: The the positive control group, compound enema group 1, compound enema group 2 compared with normal control group and negative control group, there was statistically significant(P < 0.01), suggested that local radiation caused proctitis, increased rats’ serum IL-6, IL-8, TNF-α, suggested that reducing the expression of serum IL-6, IL-8, TNF-α may be the possible mechanism of drug retention enema treating radiation proctitis. The compound enema group 1and 2 compared with the positive control group was statistically significant(P < 0.05), indicated that the compound enema group 1and 2 decreaseing levels of IL-6, IL-8, TNF-α was better than the positive control group. Conclusion: 1.A single large dose(25Gy) 6MV-X ray local irradiation method could establish the model of radiation proctitis successfully. 2. Xiaozhiling, gentamicin, glutamine, mesalazine retention enema improved the therapeutic efficacy of acute acute radiation proctitis, alleviated the degree of inflammation, damage and classification.3.Xiaozhiling, gentamicin, glutamine, mesalazine retention enema was effective in the prevention and treatment of acute radiation proctitis, reduced the incidence of chronic radiation proctitis, alleviated the degree of inflammation, damage and classification. 4. Its mechanism may be related to the inhibition of synthesis, release of inflammatory cytokines IL-6, IL-8, TNF-α. |
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