糖尿病大鼠小肠平滑肌细胞线粒体膜电位变化及其意义

目的　研究糖尿病大鼠小肠平滑肌细胞线粒体膜电位变化与细胞凋亡的关系。方法　Wistar大鼠 70只 ,随机分为 :对照组(n =30 ) ,腹腔注射等量的生理盐水。糖尿病模型组(n=4 0 ) ,以链脲菌素 6 0mg/kg腹腔注射 ;造模 2个月后行大鼠胃排空和肠道传输速度测定 ,应用激光共聚焦显微镜检测小肠平滑肌线粒体膜电位 ,脱氧核糖核苷酸末端转移酶介导的缺口末端标记技术 (TUNEL)和流式细胞仪检测细胞凋亡指数 ,Westernblot免疫印迹检测细胞色素C含量。结果　模型组大鼠小肠平滑肌细胞线粒体膜电位 (36 8.8±5 6 4 )显著低于对照组 (96 0 5± 12 6 3,P <0 0 1) ;TUNEL染色显示实验组小肠平滑肌细胞凋亡指数 (9 6 3%± 2 4 7% )显著高于对照组(3 2 3%± 1 2 8% ,P <0 0 1) ;流式细胞仪检测提示实验组小肠平滑肌细胞凋亡率为 15 0 % ,明显高于对照组 (3 0 % ,P <0 0 1)。Westernblot免疫印迹检测实验组细胞色素C含量较对照组明显增高(P <0 0 1)。结论　糖尿病大鼠的胃肠道动力改变和线粒体功能改变与细胞凋亡有关。

Mitochondrial membrane potential change and apoptosis of small intestinal smooth muscle cells in diabetic rats

Objective To investigate the relationship between mitochondrial membrane potential change and apoptosis of smooth muscle cells of the small intestine in diabetic rats. Methods Seventy Wistar rats were randomly divided into two groups: diabetic group(STZ60mg/kg intraperitonealy) and control group.The gastric empty time and intestinal transit were determined in diabetic rats 2 months after the reproduction of diabetes. Mitochondrial membrane potential in small intestinal smooth muscle cells was determined by the change in the intensity of labeling rhodamine 123 with lasor scanning confocal micrographs, and apoptosis index was assessed with the technique of terminal deoxynucleotidyl transferase mediated d-UTP nick end labeling(TUNEL) test and flow cytometry.The changes in expression of cytochrome C were determined by Western blotting. Results The mitochondrial membrane potential of small intestine smooth musele cells was significantly lowered in diabetic rats compared with normal rats. Apoptosis index in diabetic rats was significantly higher than that of normal as shown by TUNEL technic. Apoptosis rate in diabetic rats was 15%, and it was significantly higher than that of normal rat (P<0.01). The expression of cytochrome C of small intestinal smooth muscle cells in diabetic gastroparesis rats was significantly increased compared with than in normal rats. Conclusion Diabetic gastroparesis was associated with mitochondrial dysfunction and apoptosis of smooth muscle cells of the small intestine.