Regulatory effect of berberine on unbalanced expressions of renal tissue TGF-β1/SnoN and Smad signaling pathway in rats with early diabetic nephropathy

Abstract

To investigate the effect of berberine (BBR) on unbalanced expression of renal tissue TGF-beta1/SnoN and Smad signal pathway in rats with early diabetic nephropathy (DN), and discuss BBR's effect on DN rats with early diabetic nephropathy and its possible mechanism. DN rat model were established by injecting streptozotocin (STZ). The rats were divided into six groups: the control group, the model group, three BBR (50, 100, 200 mg x kg(-1)) treatment groups and the enalapril treatment group. They were orally administered once a day for five weeks. The fasting blood glucose (FBG), blood urea nitrogen (BUN), serum creatinine (Scr), urinary protein (24 h Upro) and urinary microalbumin (24 h UmAlb) were tested. The pathological changes in renal tissues were examined by optical microscopy. Immunohistochemical measures were used to detect the expressions of TGF-beta1, SnoN, Smad2/3 and Smad7 protein, and RT-PCR was used to detect TGF-beta1 mRNA in renal tissues. Compared with the model group, BBR-treated groups showed significant decrease in FBG, BUN, Scr, 24 h Upro, 24 h UmAlb, TGF-beta1 protein, mRNA and Smad2/3 protein, abnormal morphological improvement in renal tissues, and notable increase in the expressions of SnoN and Smad7 protein. BBR can maintain the dynamic balance in TGF-beta1/SnoN expression in renal tissues through Smad signaling pathway, so as to mitigate renal functional disorder in DN rats and delay DN and its development.