Effect of forsythiaside A against CCl_4-induced liver fibrosis in mice and its mechanism

Abstract

This study aims to investigate the efficacy of forsythiaside A(FTA) against CCl_4-induced liver fibrosis and the mechanism. Specifically, activities of serum alanine/aspartate aminotransferase(ALT/AST) and hydroxyproline(HYP) level in liver were detected, and pathological morphology of liver was observed based on hematoxylin-eosin(HE) staining, Masson's trichrome staining, and Sirius red staining of liver. On this basis, the effect of FTA on liver fibrosis was evaluated. The mRNA expression of actin alpha 2/α-smooth muscle actin(Acta2/α-SMA), transforming growth factor β(Tgfβ), collagen Ⅰ alpha 1(Col1 a1), and collagen Ⅲ alpha 1(Col3 a1) in liver tissue and hepatic stellate cells(HSC) was determined by qPCR, and the protein expression of α-SMA in liver tissue and HSC was measured by Western blot to assess the inhibition of FTA on HSC activation. The protein expression of α-SMA, vi-mentin(Vim), vascular endothelial cadherin(Ve-cadherin), and platelet endothelial cell adhesion molecule-1(PECAM-1/CD31) was measured by Western blot to evaluate the reverse of endothelial-mesenchymal transition(EMT) by FTA. The efficacy of FTA in relieving CCl_4-induced liver fibrosis was evidenced by the alleviation of hepatocyte necrosis, liver inflammation, and hepatic collagen deposition. FTA decreased the mRNA expression of Acta2, Tgfβ, Col1 a1, and Col3 a1 and protein expression of α-SMA both in vivo and in vitro. FTA reversed the increase of α-SMA and Vim and the decrease of CD31 and Ve-cadherin in livers from mice treated with CCl_4. Therefore, FTA alleviated CCl_4-induced liver fibrosis in mice via suppressing HSC activation and reversing EMT.