二氢杨梅素通过Sirt1通路促进自噬改善糖尿病肾病大鼠肾损伤

Dihydromyricetin Promotes Autophagy via Sirt1 Pathway to Improve Renal Injury in Rats with Diabetic Nephropathy

目的:探讨二氢杨梅素(DMY)对糖尿病肾病(DN)的保护作用及其调控自噬的机制。方法:采用55mg·kg^-1链脲佐菌素(STZ)腹腔注射大鼠建立DN模型,以血糖>16.7mmol·L^-1为建模成功。将大鼠随机分为正常对照组、模型组和低、中、高剂量DMY组,灌胃12周。运用透射电镜观察各组大鼠肾脏细胞自噬水平的变化。免疫组化检测各组大鼠肾组织自噬关键蛋白LC3和凋亡相关蛋白Bcl-2、Bax的表达水平。Westernblot检测各组大鼠肾组织Sirt1、Beclin-1蛋白的表达。结果:与正常对照组相比较,模型组自噬相关蛋白Sirt1、Beclin-1和LC3的表达均下降(P<0.05),凋亡相关蛋白Bax表达增加,Bcl-2表达下降(P<0.01)。DMY干预后,能明显促进肾脏组织自噬体的形成,显著增加肾脏组织Sirt1、Beclin-1、LC3、Bcl-2蛋白的表达(P<0.05),抑制凋亡相关蛋白Bax的表达(P<0.05)。结论:DMY可能通过激活Sirt1的表达促进自噬,抑制细胞凋亡来发挥对DN大鼠肾脏的保护作用。

Objective:To investigate the protective effect of dihydromyricetin(DMY)on diabetic nephropathy(DN)and its mechanism of autophagy.Methods:DN model was established by intraperitoneal injection of 55 mg/kg streptozotocin,and the blood glucose was>16.7 mmol·L^-1.Rats were randomly divided into normal control group,model group and low,medium and high dose DMY group,and were orally administered for 12 weeks.The changes of autophagy of kidney cells in each group were observed by transmission electron microscopy.The expression levels of LC3,Bcl-2,Bax were detected by immunohistochemistry.The expression of Sirt1 and Beclin-1 protein in renal tissue of each group was detected by Western blot.Results:Compared with the normal control group,the expression of autophagy-related proteins Sirt1,Beclin-1 and LC3 decreased(P<0.05),the expression of apoptosis-related proteins Bax increased,and the expression of Bcl-2 decreased in the model group(P<0.01).After DMY intervention,it could significantly promote the formation of autophagosomes in kidney tissue,significantly increase the expression of Sirt1,Beclin-1,LC3 and Bcl-2 proteins in kidney tissues(P<0.05),and inhibit the expression of apoptosis-related proteins Bax(P<0.05).Conclusions:DMY may play a protective role in kidney of DN rats by activating the expression of Sirt1 to promote autophagy and inhibit apoptosis.