急性放射性肠炎模型研究——两种造模方法的对比与评价

摘要

Objective To investigate the reliable methods for establishing models of acute radiation enteritis (ARE) and the criteria used to judge whether the model is successfully established.Methods A total of 98 rats were randomly divided into normal control group (group A),fractionated dose group B (4 Gy/fraction for 3 fractions),fractionated dose group C (4 Gy/fraction for 4 fractions),fractionated dose group D (4 Gy/fraction for 5 fractions),single fraction group E (12 Gy in a single fraction),single fraction group F (16 Gy in a single fraction),and single fraction group G (20 Gy in a single fraction).Abdominal irradiation was performed for all rats,and the changes in body weight and defecation were observed.Magnetic resonance imaging (MRI) was performed on days 3-5 after irradiation,and on the 4th day,anatomy was performed to measure the length of small intestine with edema,blood samples were collected to measure endotoxins,and the specimens of small intestine were collected to observe pathological changes.The independent-samples t-test was used for comparison between groups.Results After irradiation,groups D,E,F,and G experienced varying degrees of diarrhea and had positive results from endotoxins test.Group D had a longer length of small intestine with edema than group C (P=0.00) and had a similar length as group E (P=0.46).Groups E,F,and G showed dilation and dropsy in the intestinal canal on MRI,and groups F and G showed patchy signals of dropsy in the abdominal cavity.Groups F and G showed varying degrees of necrosis in the small intestine and died within 14 days after irradiation.Conclusions When the radiation dose is 33-46 Gy (biologically equivalent dose),both single dose and fractionated dose can successfully establish the model of ARE,while fractionated dose can be better controlled.%目的 探索可靠的急性放射性肠炎造模方法及判断造模成功的标准.方法 98只大鼠随机分为7各组,即正常对照A组、分次给量B组(4 Gy/次3次)、分次给量C组(4 Gy/次4次)、分次给量D组(4 Gy/次5次)、单次给量E组(12 Gy/次1次)、单次给量F组(16 Gy/次1次)、单次给量G组(20 Gy/次1次).腹部照射,观察照射后大鼠体重、排便等的改变.照射后第3～5天行MR,第4天解剖测水肿小肠长度、采血测内毒素、取小肠标本观察病理改变.组间比较行成组t检验.结果 D、E、F和G组照射后发生不同程度腹泻,且内毒素检测结果为阳性.水肿小肠长度占比D组比C组增高(P=0.00),E组与D组相近(P=0.46).E组、F组与G组MRI见肠管扩张积液,F组与G组腹腔内见片状积液信号.F组与G组小肠发生不同程度坏死,照射后14 d内全部死亡.结论 当照射剂量为33～46 Gy (BED)时,单次给量与分次给量两种造模方法均可成功复制急性放射性肠炎模型,但后者更利于把控.