达格列净通过上调SIRT1增强糖尿病肾病大鼠肾脏细胞自噬从而抑制足细胞损伤

Dapagliflozin enhances renal cell autophagy in diabetic kidney disease rats by up-regulating expression of SIRT1,thereby preventing podocyte damage

目的:探讨达格列净(dapagliflozin)是否通过上调沉默信息调节因子2相关酶1(silent information regulator factor 2-related enzyme 1,SIRT1)的表达来增强糖尿病肾病大鼠肾脏细胞自噬从而抑制其足细胞损伤。方法:采用高脂饮食和低剂量链脲佐菌素(streptozotocin,STZ)建立糖尿病肾病大鼠模型,将模型大鼠随机分为糖尿病组及达格列净组,另设对照组,每组6只,记录体重、血糖和饮水量变化。成模2周后达格列净组与糖尿病组大鼠分别开始使用达格列净与生理盐水灌胃4周。灌胃结束后收集所有大鼠24 h尿液、血液和肾脏标本。测定血清葡萄糖、血清胰岛素、血清肌酐、尿总蛋白和尿白蛋白,记录肾脏重量,电镜下观察肾脏结构变化,免疫荧光和Western blot分别检测各组SIRT1、自噬标志物微管相关蛋白1轻链3(microtubule-associated protein 1 light chain 3,LC3)、be⁃clin⁃1以及足细胞标志物NPHS2的表达情况。结果:电镜下达格列净组肾小球区病变轻于糖尿病组(P<0.05)。达格列净组大鼠肾重/体重比及血清葡萄糖、血清胰岛素、24 h尿总蛋白、24 h尿白蛋白量均较糖尿病组显著降低(P<0.05)。达格列净组肾组织SIRT1、beclin⁃1、NPHS2蛋白表达水平及自噬标志物LC3-II/LC3-I蛋白比值均较糖尿病组升高(P<0.05)。结论:达格列净通过上调SIRT1的表达增强糖尿病肾病大鼠肾脏细胞自噬从而抑制其足细胞损伤。

AIM:To investigate whether dapagliflozin can enhance renal cells autophagy and inhibit podocytes damage in diabetic nephropathy rats by upregulating the expression of silent information regulator factor 2-related enzyme 1(SIRT1).METHODS:The diabetic rat model was established by using high-fat diet fed combined with low dose streptozotocin(STZ)injection.The model rats were randomly divided into diabetes group,dapagliflozin group,and control group.Changes of body weight,blood glucose and water intake were recorded.Two weeks after the establishment of the model,therats in dapagliflozin group and the diabetes group began to be treated with dapagliflozin or normal saline respectively for 4 weeks.24-hour urine,blood and kidney samples of all rats were collected after treatment.Serum glucose,insulin,creatinine,urinary total protein and urinary albumin were measured.Kidney weight was recorded and renal structural changes were observed under electron microscope.The expression levels of SIRT1,autophagy marker microtubuleassociated protein 1 light chain 3(LC3),beclin-1 and podocyte marker NPHS2 were detected by immunofluorescence and Western blot.RESULTS:Under electron microscope,the glomerular lesion in the dapagliflozin group was slighter than that in the diabetes group.The ratio of kidney weight to body weight,serum glucose,serum insulin,serum creatinine,24-hour urinary total protein and 24-hour urinary albumin in the dapagliflozin group were significantly lower than those in the diabetes group(P<0.05).SIRT1,beclin-1,NPHS2 protein expression level and LC3-II/LC3-I protein ratioin dapagliflozin group were significantly higher than those in diabetes group(P<0.05).CONCLUSION:Dapagliflozin promotes renal autophagy in diabetic kidney disease rats by up-regulating the expression of SIRT1,thereby preventing podocyte damage.