玉米须水提物对2型糖尿病肾病大鼠转化生长因子-β_1和纤维连接蛋白表达的影响

Effect of aqueous extract from stigma maydis on expressions of TGF-β_1 and FN in renal lesion of type 2 diabetic nephropathy rats

目的研究玉米须水提物对2型糖尿病肾病大鼠肾组织中转化生长因子-β1(TGF-β1)和纤维连接蛋白(FN)表达的影响,探讨其可能的作用机制。方法采用高糖高脂饲养加小剂量链脲佐菌素(STZ)诱导2型糖尿病肾病大鼠模型,将实验动物分为正常对照组、模型对照组和玉米须水提物低、中和高剂量组,共5组。给药8周后,测定各组大鼠空腹血糖、体重、肾重、血清尿素氮、血肌酐和24 h尿蛋白;免疫组化法分析TGF-β1表达水平;实时定量RT-PCR定量检测肾组织TGF-β1和FN的表达水平。结果与模型对照组比较,中和高剂量组的玉米须水提物可显著降低糖尿病肾病大鼠血糖、肾指数、血清尿素氮、血肌酐和24 h尿蛋白(P<0.05或P<0.01),明显降低肾组织中TGF-β1和FN m RNA的表达量(P<0.05或P<0.01)。结论玉米须水提物能够降低糖尿病大鼠血糖、肾指数、血清尿素氮、血肌酐和24 h尿蛋白的水平,下调肾病大鼠肾组织中TGF-β1和FN的表达,调节细胞外基质的生成和降解,从而减轻糖尿病肾病大鼠肾脏的病理损害,发挥其肾脏保护作用。

【Objective】To study the effect of aqueous extract from stigma maydis（AESM） on the expression of transforming growth factor-β1（TGF-β1） and fibronectin（FN） in renal lesion of type 2 diabetic nephropathy rats and its effective mechanism.【Methods】Type 2 diabetic nephropathy rat models were induced by high-sugar and highfat dietary feeds and low dose streptozotocin（STZ）. Experimental rats were randomly divided into five groups： Normal control group, Model control group, AESM low, middle and high dose group. Eight weeks after treatment, levels of fasting blood glucose（FBG）, body weight（BW）, kidney weight, blood urea nitrogen（BUN）, serum creatinine（SCr） and24 h urinary protein were measured respectively; the expression of TGF-β1in renal tissue was analyzed by immunohistochemistry method; the expressions of TGF-β1and FN in renal tissue were analyzed and detected by realtime RT-PCR technology. 【Results】Compared with Model control group, AESM of middle and high dose could remarkably lower the level of FBG, kidney index, blood urea nitrogen（BUN）, serum creatinine（SCr） and the 24-hour urinary protein（P〈0.05 or P〈0.01）, and dominantly decrease the expression of TGF-β1and FN in renal tissue（P〈0.05 or P〈0.01）.【Conclusions】AESM can lower the level of FBG, kidney index, blood urea nitrogen（BUN）, serum creatinine（SCr） and the 24-hour urinary protein in diabetic nephropathy rats, downregulate the expression of TGF-β1and FN in renal tissue, and regulate the synthesis and degradation of extracellular matrix. Thus, AESM can alleviate renal pathological lesion, and has a renal protective effect in diabetic nephropathy rats.