Effect of Qiwei Granules on TGF-β_1/Smads Signaling Pathway in Renal Tissue in KK-Ay Mice

Objective To research the molecular mechanism of Qiwei Granules [granules of Huangqi (Radix Astragali) and Weimao (Euonymi Ramulus)] to treat interstitial fibrosis in diabetic nephropathy (DN). Methods KK-Ay mice with spontaneous type 2 diabetes were fed with high-fat fodder to establish DN models. Forty-five successful model mice were randomized into model group, Chinese medicine group and western medicine group, with 15 in each. The Chinese medicine group was gavaged with 20 g/(kg·d) crude drug of Qiwei Granules and the western medicine group was gavaged with 10 mg/(kg·d) valsartan capsules. Fifteen male C57BL/6J mice were chosen as the normal group. The administration lasted for 12 weeks. The expressions of transforming growth factor-β1 (TGF-β1), phosphorylated-Smad2 (P-Smad2), P-Smad3, Smad7, integrin-linked kinase (ILK) and ILK mRNA were examined with immunohistochemistry, Western blot and quantitative real-time polymerase chain reaction respectively. Results Comparing with the normal group, the expressions of TGF-β1, P-Smad2, P-Smad3, ILK and ILK mRNA in the model group were significantly increased (P0.01), but the expression of Smad7 was significantly decreased (P0.01). Comparing with the model group, the expressions of TGF-β1, P-Smad2, P-Smad3, ILK and ILK mRNA in both administration groups were significantly decreased (P0.05 or P0.01), but the expression of Smad7 was significantly increased (P0.01). Comparing with the western medicine group, the expression of P-Smad3 was significantly increased in the Chinese medicine group (P0.05). Conclusion Qiwei Granules can block TGF-β1/Smads signaling pathway and delay the progression of renal interstitial fibrosis by down-regulating the expressions of TGF-β1, P-Smad2, P-Smad3 and ILK and up-regulating the expression of Smad7.