腹部辐射诱发大鼠肠黏膜损伤模型的建立

CREATION OF MODEL OF INTESTINAL MUCOSA STRUCTURE DAMAGE INDUCED BY ABDOMINAL RADIATION IN RATS

目的建立稳定及符合辐射性肠黏膜屏障损伤研究的动物模型。方法将SD大鼠随机分为正常对照组(A组,10只)和B、C、D 3个照射组(每组20只)。照射组采用直线加速器一次性辐射腹部,照射剂量依次为8.5、9.09、.5 Gy,辐射范围为自剑突至肛门;A组不进行照射。于辐射后第4天取各组大鼠距屈氏韧带10 cm处小肠制作标本,光镜下测量绒毛-隐窝轴(CVA)长度,电镜下观察小肠黏膜结构;采用鲎试剂测定血浆内毒素水平。结果辐射后第4天,B、C、D组大鼠死亡率分别为10%、30%、60%。各组CVA长度比较,A组和B组差异无显著性(P>0.05),C组低于A、B组,D组低于A、B、C组,差异均有显著意义(F=100.480,q=4.617～18.560,P<0.05)。C组大鼠的血浆内毒素水平高于A、B组,D组高于A、B、C组,差异有显著意义(F=50.468,q=5.380～15.898,P<0.05)。电镜下可见各照射组大鼠肠黏膜上皮细胞脱落,溃疡形成,无正常细胞结构,基底层显露,并可见细菌穿透黏膜层。结论辐射性肠黏膜损伤大鼠模型建立成功,9.0 Gy剂量全腹照射所产生的大鼠放射性肠炎模型适用于辐射性肠黏膜屏障损伤的研究。

Objective To establish a stable animal model that consistent with the requirements for research of radiation damage of intestinal mucosal barrier. Methods SD rats were randomly divided into control group（group A,10 rats） and radiation groups B,C,D（20 in each group）.The rats in groups B,C,and D were given single fraction irradiation on abdomen with linear accelerator,the dosage being 8.5,9.0,and 9.5 Gy,respectively,the radiation scope was from the xyphoid to anus.No radiation was given to the rats in group A.At day 4 after radiation,a segment of intestine,10 cm from Treitz＇s ligament,was taken for making specimen.The length of crypt-villus axis（CVA） was measured light-microscopically,and intestinal mucous membrane structure observed electron-microscopically.Plasma endotoxin levels were detected by using tachypleus amebocyte lysate. ResultsAt day 4 after radiation,death rates of the rats in groups B,C,and D were 10%,30%,and 60%,respectively.A comparison of the length of CVA among the four groups showed： the difference between groups A and B was not significant（P0.05）;the length of CVA was shorter in group C than that in groups A and B;and that in group D was shorter than that in groups A,B,and C,the differences were all significant（F=100.48,q=4.617-18.560,P0.05）.Plasma endotoxin concentration of group C was higher that that of groups A and B,that of group D was higher than that of groups A,B and C（F=50.468,q=5.380-15.898,P0.05）.Electron microscopically,intestinal epithelial cell shedding,ulcer formation,no normal cellular structure,exposure of basal lamina,and bacteria penetrating the stratum mucosum could be seen. Conclusion A model of radiation-induced damage of intestinal mucosal structure in the rat is created successfully.The model of radiation enterocolitis caused by total abdominal irradiation of a dose of 9.0 Gy is applicable to research for radiation damage of mucosa barrier of intestine.