糖尿病大鼠主动脉自噬水平的变化及雷帕霉素的干预作用

Expression of autophagy level in the aorta of diabetic rats and the intervention effect of rapamycin

目的观察糖尿病大鼠主动脉自噬水平的变化及雷帕霉素的干预作用,探讨雷帕霉素是否通过调节自噬、内质网应激和细胞凋亡对糖尿病大鼠主动脉产生保护作用。方法雄性SD大鼠用随机数字表法分为正常对照组、糖尿病组和雷帕霉素干预组。采用链脲佐菌素制备1型糖尿病大鼠模型。雷帕霉素干预组给予雷帕霉素2mg/(kg·d)灌胃。于实验第8周留取血标本,用于血生物化学指标和脂联素水平检测,然后处死动物并迅速取出胸主动脉和腹主动脉,测定主动脉Beclin1、微管相关蛋白轻链3(LC3)、p62、C/EBP同源蛋白(CHOP)、Caspase-12、葡萄糖调节蛋白78(GRP78)、Bax和Bcl-2的mRNA和蛋白表达。结果与正常对照组比较,糖尿病组大鼠血清脂联素水平显著降低(P<0.05),主动脉壁增厚,内皮严重受损,主动脉Beclin1、LC3的mRNA和蛋白表达水平及Bcl-2mRNA表达水平显著降低(P <0. 05),主动脉p62、CHOP、Caspase-12和GRP78的mRNA和蛋白表达水平及Bax mRNA表达水平显著升高(P<0.05)。与糖尿病组比较,雷帕霉素干预组大鼠血清脂联素水平显著升高(P<0.05),主动脉组织病理改变显著减轻,主动脉Beclin1、LC3的mRNA和蛋白表达水平及Bcl-2 mRNA表达水平显著升高(P<0.05),主动脉p62、CHOP、Caspase-12和GRP78的mRNA和蛋白表达水平及Bax mRNA表达水平显著降低(P<0.05)。结论糖尿病大鼠主动脉组织自噬水平降低,雷帕霉素可能通过激活自噬和减轻内质网应激和细胞凋亡水平对糖尿病大鼠主动脉产生保护作用。

Aim To investigate the expression of autophagy level in the aorta of type 1 diabetic rats and the intervention effect of rapamycin,and determine whether rapamycin has a protective effect on the aorta of diabetic rats by regulating autophagy,endoplasmic reticulum stress,and apoptosis. Methods Male SD rats were randomly divided into three groups: normal control group,diabetes mellitus group,and rapamycin intervention group. Diabetic rats were induced by a single intraperitoneal injection of streptozotocin. The rats in the rapamycin intervention group were given rapamycin in a dose of 2 mg/kg once a day by gavage. After rapamycin treatment for 8 weeks,blood samples were collected for biochemical indicators and adiponectin detection. The protein or mRNA expression of Beclin1,microtubule-associated protein light chain 3( LC3),p62,C/EBP homologous protein( CHOP),Caspase-12,glucose-regulated protein 78( GRP78),Bax and Bcl-2 were assayed by Western blot or real-time fluorescence quantitative PCR. Results Compared with normal control group,the level of serum adiponectin in diabetic rats was significantly decreased( P< 0.05),aortic wall was thicker,endothelium was severely damaged,the mRNA and protein expression of Beclin1 and LC3 and the mRNA expression of Bcl-2 in aorta were significantly decreased( P<0.05),and the mRNA and protein expression of p62,CHOP,Caspase-12 and GRP78 and the mRNA expression of Bax in aorta were significantly increased( P<0.05).Compared with diabetes mellitus group,the level of serum adiponectin in rapamycin intervention group was significantly increased( P<0.05),the pathological changes of aorta tissue were significantly alleviated,the mRNA and protein expression of Beclin1 and LC3 and the mRNA expression of Bcl-2 in aorta were significantly increased( P<0.05),and the mRNA and protein expression of p62,CHOP,Caspase-12 and GRP78 and the mRNA expression of Bax in aorta were significantly decreased( P<0.05). Conclusions The level of autophagy in aorta tissue of diabetic rats decreased.Rapamycin may protect the aorta of diabetic rats by activating autophagy and alleviating endoplasmic reticulum stress and cell apoptosis.