SIRT1/PGC-1α在高糖状态下线粒体氧化应激损伤致足细胞凋亡中的作用

Role of SIRT1/PGC-1αPathway in Mitochondrial Oxidative Stress Injury to Podocyte Apoptosis Under High Glucose State

目的:探讨SIRT1/PGC-1α通路在高糖状态下线粒体氧化应激损伤至足细胞凋亡中的作用。方法:采用高糖高脂饮食联合小剂量链脲佐菌素腹腔注射建立2型糖尿病大鼠模型,将造模成功的大鼠分为糖尿病模型组和白藜芦醇治疗组。在给药10周末,测定各组大鼠肾质量指数、肾功能和24 h尿蛋白(UTP)变化,电镜及光镜下观察肾脏病理改变,硫代巴比妥酸法检测肾脏MDA含量,WST-1法检测SOD活性,大鼠肾组织SIRT1、PGC-1α、Caspase3及Synaptopodin蛋白表达水平用Western blot法和IHC法检测,大鼠肾组织ROS、Bcl-2、Caspase9、Desmin蛋白水平用IHC法检测。结果:与正常组比较,模型组大鼠UTP明显上升(P<0.05),SOD表达减少,MDA,ROS明显增多(P<0.05),SIRT1,PGC-1α的蛋白表达水平明显下降(P<0.05),Bcl-2蛋白表达水平下降,Caspase9、Caspase3表达升高(P<0.05),Desmin蛋白表达增多,Synaptopodin蛋白表达减少(P<0.05);与模型组比较,白藜芦醇组UTP水平下降,SOD活性升高,MDA、ROS含量显著下降(P<0.05);SIRT1、PGC-1α蛋白表达增多(P<0.05),Bcl-2蛋白表达上升,Caspase9、Caspase3表达下降(P<0.05),Desmin蛋白表达减少,Synaptopodin蛋白表达升高(P<0.05)。结论:糖尿病肾病大鼠存在明显的线粒体氧化应激损伤,白藜芦醇可以减少高糖状态下足细胞凋亡,此作用可能与上调SIRT1/PGC-1α表达改善线粒体功能,减少ROS生成有关。

Objective:To investigate the role of SIRT1/PGC-1αpathway in mitochondrial oxidative stress injury to podocyte apoptosis under high glucose state.Methods:Type 2 diabetic rats model were established by high-fat and high-sugar diet combined with low-dose streptozotocin(STZ)intraperitoneal injection.Rats were randomly into a model group and a resveratrol group after modeling.At the end of 10 weeks of administration,renal mass index,urea nitrogen(BUN),serum creatinine(Scr),and 24-hour urine total protein(UTP)levels of each group were detected,the renal pathological changes were observed by electron microscope and light microscope,malondialdehyde(MDA)content of kidney was detected by thiobarbituric acid method,and superoxide dismutase(SOD)activity was detected by WST-1 method.The protein expression levels of SIRT1,PGC-1α,Caspase3 and Synaptopodin in renal tissue were detected by Western blotting and immunohistochemistry(IHC).The protein expression levels of ROS,Bcl-2,Caspase9 and Desmin were detected by IHC.Results:Compared with normal group,the model group showed increased UTP(P<0.05),decreased SOD,elevated MDA and ROS(P<0.05),down-regulated protein expression of SIRT1 and PGC-1α(P<0.05),enhanced protein expression of Caspase9 and Caspase3,declining protein expressiom of Bcl-2(P<0.05),elevated protein expression of Desmin and diminished protein expression of Synaptopodin(P<0.05).Compared with the model group,the resveratrol group displayed declining UTP(P<0.05),up-regulated SOD,decreased MDA and ROS(P<0.05),up-regulated protein expression of SIRT1 and PGC-1αPGC-1α,diminished protein expression of Caspase9 and Caspase3,elevated protein expression of Bcl-2(P<0.05),diminished protein expression of Desmin and elevated protein expression of Synaptopodin(P<0.05).Conclusion:There is significant mitochondrial oxidative stress damage in diabetic nephropathy rats,and resveratrol can reduce podocytes apoptosis under high glucose state,which may be related to the up-regulated of SIRT1 and PGC-1αexpression to improve mitochondrial function and reduce ROS production.