Icariin inhibits myofibroblasts proliferation and attenuates renal fibrosis in 5/6 nephrectomized rats
Objective To observe the effect of icariin on proliferation of renal interstitial myofibroblasts in 5/6 nephrectomized rats and explore its mechanism.Methods The rats were divided into sham operation group,model group,icariin high-dose group and icariin low-dose group.In the sham operation group,only the renal envelope was separated without nephrectomy,and the model group and icariin group underwent 5/6 nephrectomy,with seven rats in each group.Icariin was given 50 mg·kg-1 in low-dose icariin group and 100 mg·kg-1 in high-dose icariin group,once a day.The serum of rats was collected at the end of the 14th week to detect creatinine(Scr)and urea nitrogen(BUN).Part of the kidney was taken and histological changes were observed by routine pathological examination.Sirian red staining was used to detect renal interstitial fibrosis.The expressions of α-smooth muscle actin(α-SMA),transforming growth factor-β1(TGF-β1),phospho-small mothers against decapentaplegic homolog 2/3(p-SMAD2/3)and DNA methyltransferase 3A(Dnmt3a)in kidney tissues were detected by immunohistochemistry.The expressions of α-SMA,TGF-β1 and Dnmt3a in other kidney tissues were detected by Western blotting.Results HE and Sirius red staining showed that renal tubules in the model group were dilated or atrophied,with a large amount of fibrous tissue hyperplasia and collagen deposition,and scattered inflammatory cell infiltration.Immunohistochemical results showed that the expression of α-SMA,TGF-β1 and its downstream molecule p-Smad2/3 were significantly increased in the model group.The expression of DNA methyltransferase Dnmt3a was significantly increased.Icariin treatment can alleviate renal pathological injury,inhibit abnormal proliferation of myofibroblasts,improve renal interstitial fibrosis,and down-regulate the expression of α-SMA,TGF-β1,p-Smad2/3 and Dnmt3a.The inhibitory effect of icariin high-dose group on Dnmt 3a expression was stronger than that of icariin low-dose group,but there was no significant difference in the effect of other indicators between icariin high-dose group and low-dose group.Conclusion Icariin shows an antifibrotic effect in 5/6 nephrectomy induced CKD rats,the mechanism may be through regulating TGF-β1-induced DNA hypermethylation to inhibit myofibroblasts proliferation and attenuate renal interstitial fibrosis.
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