Dendrobium Mixture Improved Diabetic Nephropathy in db/db Mice by Regulating TGF-β1/Smads Signal Transduction

Abstract

Background

Dendrobium mixture (DMix) is an effective treatment for diabetic nephropathy (DN), but the underlying molecular mechanism remains unclear. In this study, we investigated whether DMix regulates the transforming growth factor-β1 (TGF-β1)/Smads signal transduction pathway.

Methods

Twenty-four db/db mice were randomly divided into three groups: the model, DMix, and gliquidone groups, while eight db/m mice were selected as the normal control group. The drug was administered by continuous gavage for 8 weeks. Body weight (BW), kidney weight (KW), kidney index, fasting blood glucose (FBG), blood lipid, 24-hour urinary albumin excretion rate, blood urea nitrogen, and serum creatinine levels were measured. Pathological changes in the renal tissue were observed using a light microscope. Real-time quantitative PCR and immunohistochemical staining were used to detect mRNA expression of TGF-β1 and alpha-smooth muscle actin (α-SMA) genes and proteins, respectively, in renal tissues. TGF-β1, Smad2, p-Smad2, Smad3, p-Smad3, and α-SMA expression levels were measured using western blotting.

Results

DMix significantly reduced FBG level, BW, KW, and blood lipid level, and improved renal function in db/db mice. Histopathology showed that DMix alleviated glomerular mesangial cell proliferation and renal interstitial fibrosis in db/db mice. Additionally, DMix reduced protein and mRNA expression of TGF-β1 and α-SMA, and inhibited Smad2 and Smad3 phosphorylation.

Conclusions

The findings suggest that DMix may inhibit renal fibrosis and delay the progression of DN by regulating the TGF-β1/Smads signaling pathway. Key words: Diabetic nephropathy, Dendrobium mixture, TGF-β1/Smads signaling pathway

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