Tangke Decoction Improves Diabetic Kidney Damage Based On The MiR-21/TGF-β1/Smad Pathway

ObjectiveTo investigate the effect of Tangke decoction on the kidney of diabetic rats with renal damage and its possible mechanism by observing the changes of miR-21/TGF-β1 / Smad signaling pathway.Methods50 male SPF rats were fed one week adaptively and 10 rats were randomly selected as the blank control group.The other rats were injected with streptozotocin(STZ)once a day for duplicating the diabetic model and developed for 2 weeks to develop diabetic nephropathy spontaneously.They were randomly divided into 4 groups: model group,Fosinopril sodium group(0.9mg/kg),low dose Tangke decoction group(4.5g/kg)and high dose Tangke decoction group(18g/kg)and gavage once daily.The general conditions of rats in each group were observed.And the blood glucose,body weight,BUN,Scr and 24 h urine protein were monitored.The morphological and pathological changes of kidney were observed by HE staining and the distribution of Smad3 and Smad7 protein in kidney were detected by immunohistochemistry.The mRNA expression levels of miR-21,Smad3,Smad7 and FN1 in renal tissues were detected by real-time fluorescence quantitative PCR(QRTPCR).The protein expression levels of FN1,PKC,Smad3,Smad7,TGF-β1,VEGF and p38 in renal tissues were detected by Western-Blot.ResultsThe levels of blood glucose,body weight,BUN,Scr and 24 h urinary protein in the low-dose and high-dose groups of the model group,fosinopril sodium tablet group and the Tangke decoction group were significantly decreased(P<0.01).They could effectively delay the renal arteriolar hyaline degeneration,inhibit glomerular basement membrane thickening and renal hypertrophy.They also could inhibit the expansion of the mesangial area,reduce the mesangial matrix increase and ease the process of renal tubular and renal interstitial fibrosis.The protein expression levels of FN1,PKC,Smad3,TGF-β1,VEGF and p38 were significantly down-regulated and Smad7 protein was significantly up-regulated(P <0.01).The mRNA expression level of miR-21,Smad3 and FN1 in renal tissues were decreased and Smad7 was increased by real-time fluorescence quantitative PCR(P<0.01).The result of immunohistochemistry was consistent with Western-blot.Conclusions1.Tangke decoction can regulate the expression of miR-21/TGF-β1/Smad signal pathway to reduce the process of renal injury induced by STZ in diabetic nephropathy.2.Tangke decoction can improve the physical status of diabetic nephropathy rats,such as blood sugar,left kidney weight,kidney weight/body weight,urea nitrogen(BUN),serum creatinine(Scr)and 24 h urinary protein,body weight.At the same time,Tangke decoction can effectively delay the process of glomerular tubular and interstitial Hyaline change,Mesangial matrix thickening and renal tubule and interstitial fibrosis.3.Tangke decoction could decrease the protein expression of FN1,Smad3,TGF-β1,PKC,p38 and VEGF,increase the expression of Smad7.Also,It could down-regulate the level of FN1 mRNA,Smad3 mRNA and miR-21,up-regulate Smad7 m RNA,and improves diabetic kidney damage.