葡萄籽原花青素通过Nrf2调节糖尿病大鼠肾组织GSTM的表达

目的: 研究葡萄籽原花青素(GSP)对糖尿病大鼠肾保护作用的分子生物学机制,为GSP治疗糖尿病肾病提供实验依据。方法: 雄性Wistar大鼠尾静脉注射0.1%链脲佐菌素(STZ)建立糖尿病大鼠模型,成模后随机分为糖尿病组(DM组)和糖尿病GSP治疗组(GSP组,GSP 250 mg·kg^-1·d^-1),另设正常对照组(C组)。观察24周后测量大鼠体重、收缩压、肾重/体重和24 h尿蛋白定量;采血测定空腹血糖(FPG)、尿素氮(BUN)、肌酐(SCr)和糖基化血红蛋白(HbA1c);观察糖尿病大鼠肾脏病理改变,并应用Western blotting和免疫组化法测定肾组织谷胱甘肽S-转移酶μ亚型(GSTM)和核因子E2相关因子2(Nrf2)的表达。结果: 实验开始时3组大鼠体重无明显差异(P>0.05),24周时DM组大鼠较C组大鼠体重显著下降(P<0.01),治疗后GSP组大鼠体重较DM组增加,但无显著差异(P>0.05)。第24周时DM组大鼠与C组相比较,收缩压、FPG、HbA1c、肾重/体重、24 h尿蛋白定量、BUN和SCr水平显著升高(P<0.01)。治疗后GSP组大鼠与DM组比较FPG和HbA1c水平降低,但无显著差异(P>0.05),收缩压、24 h尿蛋白定量和肾重/体重显著降低,(P<0.01),BUN和SCr水平显著降低(P<0.05)。GSP组肾组织病理改变较DM组改善。GSTM和Nrf2表达在DM组表达较C组上调,在GSP组治疗后回调(P<0.05)。结论: GSP可能通过Nrf2下调GSTM表达而起肾保护作用。

Grape seed proanthocyanidin regulates expression of GSTM through Nrf2 in renal tissues of STZ-induced diabetic rats

AIM: To investigate the potential mechanisms of renoprotective effect of grape seed proanthocyanidin (GSP) on diabetic nephropathy.METHODS: Male Wistar rats were injected with 1% streptozotocin (STZ) intravenously to induce diabetes mellitus (DM). The diabetic rats were randomly divided into 2 groups: diabetes group (DM group) and GSP treatment group (GSP group, GSP 250 mg·kg^-1·d^-1). The normal Wistar rats served as control (C group). Body weight (BW), systolic pressure, kidney weight/body weight (KW/BW), fasting plasma glucose (FPG), blood urea nitrogen (BUN), serum creatinine (SCr), glycosylated hemoglobin (HbA1c) and 24 h urine protein were determined 24 weeks after STZ intervention. The pathological changes of the renal tissues were observed. The protein levels of glutathione S-transferase mu (GSTM) and nuclear factor-erythroid 2-related factor 2 (Nrf2) in the renal tissues were determined by Western blotting and immunohistochemistry. RESULTS: Compared with C group, BW in diabetic rats decreased (P<0.01). The levels of systolic pressure, FPG, HbA1c, KW/BW, 24 h urine protein, BUN and SCr in DM group were higher than those in C group (P<0.01). After treated with GSP, the levels of systolic pressure, KW/BW, 24 h urine protein, BUN and SCr in DM rats were lower than those in DM rats without treatment (P<0.01 or P<0.05). The pathological changes were ameliorated in GSP group. The expression of GSTM and Nrf2 was up-regulated in the kidneys of diabetic rats and down-regulated to the normal levels after GSP treatment. CONCLUSION: The renoprotective effect of GSP is associated with the down-regulation of GSTM through modulating the expression of Nrf2.