ABSTRACT
Objective To investigate the role and its mechanisms of tea polyphenols (TP) in the prevention of diabetic renal fibrosis.Methods Mouse model of diabetes mellitus was induced by high-fat diet combined with intraperitoneal injection of streptozotocin (STZ,50 mg/kg).Real-time quantitative polymerase chain reaction (RT-PCR) and Western blotting were used to determine the transcription and expression of genes related to the renal fibrosis.Results Diabetic mouse model was successfully established by injection of high-fat diet plus STZ.The transcription of E-cadherin was decreased and transcriptions of genes related to the renal fibrosis such as transforming growth factor β1 (TGF-β1),vimentin,α-smooth muscle actin (α-SMA),fibronectin,collagen Ⅰ,and collagen Ⅳ were increased in the renal tissues of diabetic mice,which indicated the diabetic nephropathy with renal fibrosis in diabetic mice.Treatment of diabetic mice with TP for 8 weeks could reverse the process of diabetic nephropathy with renal fibrosis in accompanied with the increase of E-cadherin transcription and decrease of TGF-β1-targeted genes such as vimentin,α-SMA,fibronectin,collagen Ⅰ,and collagen Ⅳ in the renal tissues of diabetic mice.Moreover,incubation of normal rat kidney proximal tubular epithelial cell line (NRK-52E) cells with TGF-β1 could also induce the changes in fibrotic morphological and transcription or expression of fibrosis related genes,and all effects of TGF-β1 could be inhibited by TP treatment in NRK-52E cells.Conclusions These results indicate that chronic treatment with TP may relieve renal fibrosis of diabetic nephropathy through the inhibition of TGF-β signaling pathway and provide important experimental data for the prevention and treatment of diabetic nephropathy.
ABSTRACT
Objective To study the effects of glimepiride and short-term intensive therapy with insulin on plasma glucose and beta-cell function in newly diagnosed type 2 diabetic patients.Methods 80 newly diagnosed type 2 diabetic patients were divided into two groups of 40 patients each and randomly treated with insulin or glimepiride plus metformin for 8 weeks.The FBG,2hPBG,HbA_1c,improvement of beta-cell function were measured before and after intensive therapy in each group.Results After the treatment,FBG,2hPBG,HbA_1c were significantly decreased (all P<0.001) in each group;FCP and 2hPCP were increased(P<0.05)in each group.Conclusion Glimepiride or short-term intensive therapy with insulin plus metformin could effectively improve glycemic control and beta-cell function in newly diagnosed type 2 diabetic patients.