Effect and mechanism of Qishishenshu Capsule on renal fibrosis in mouse early diabetic nephropathy
Objective To investigate the therapeutic effect and underlying mechanism of Qishishenshu Capsule on renal fibrosis in mice with early diabetic nephropathy(DN).Methods A DN mouse model was established by multiple injections of streptozotocin.The mice were randomly divided into a normal group(NC),model group(DN),and Qishi group(QS)(0.9 g/(kg·d)),with eight mice in each group.Mice were gavaged continuously for 4 weeks,and fasting blood glucose(FBG)was measured weekly.Four weeks later,urinary albumin/creatinine(UACR),serum creatinine,and blood urea nitrogen were measured.Hematoxylin-eosin,periodicacid-Schiff,and Sirius red staining were used to analyze renal pathological changes.Real-time fluorescence quantitative reverse-transcription polymerase chain reaction was used to detect the mRNA levels of fibronectin(FN),collagen type Ⅰ alpha 1(Col1a1),and α-smooth muscle actin(α-SMA).Immunohistochemistry and Western blot were performed to detect FN,collagen type Ⅰ(Collagen Ⅰ),collagen typeⅢ(Collagen Ⅲ),α-SMA,Podocin,Nephrin,and transforming growth factor-β1/SMAD family member2/3(TGF-β1/Smad2/3)pathway-related proteins.Results Compared with mice in the NC group,those in the DN group showed significantly higher levels of FBG and UACR(P<0.001),and mesangial hyperplasia,basement membrane thickening,and collagen deposition in the renal tissue.The mRNA levels of FN,Col1a1,and α-SMA were increased(P<0.05).Protein levels of Podocin and Nephrin were decreased(P<0.05).The levels of FN,Collagen I,Collagen Ⅲ,α-SMA,and TGF-β1/Smad2/3 pathway proteins were increased(P<0.05).Compared with the DN group,the QS group's level of UACR was decreased(P<0.05),their renal pathological injury was alleviated,and mRNA levels of FN,Collagen Ⅰ,andα-SMA were attenuated(P<0.05);whereas their protein levels of Podocin and Nephrin were elevated(P<0.05).The levels of FN,Collagen Ⅰ,Collagen Ⅲ,α-SMA,and TGF-β1/Smad2/3 pathway proteins were also decreased(P<0.05).Conclusions Qishishenshu Capsule improved renal fibrosis in DN mice,probably through the inhibition of the TGF-β1/Smad2/3 signaling pathway.