Yu Gan Long reduces rat liver fibrosis by blocking TGF-β1/Smad pathway and modulating the immunity

Yu Gan Long (YGL) is a Chinese traditional herbal medicine that has been used in the treatment of liver fibrosis for many years in clinical practice. However, its anti-hepatofibrotic mechanism has not been studied yet. In this study, the effect and mechanism of YGL in reducing liver fibrosis was demonstrated in vivo. Our results showed that liver fibrosis biomarkers collagen IV (Col IV), type III precollagen (PCIII), hyaluronuc acid (HA) and laminin (LN), were increased after CCl₄ treatment and decreased by YGL. Among the liver fibrosis indicators, α-smooth muscle actin (α-SMA) was decreased by YGL in the CCl₄-treated rats, while MMP2 and MMP9 was upregulated followed by TIMP1 downregulation. Proteins involved in liver fibrosis such as p-Smad2, p-Smad3 and Smad4 were down-regulated, while Smad7 protein was up-regulated by YGL after CCl₄-induced liver damage. YGL also suppressed the increase of TGF-β1, TNF-α, IL-1β, IL-6, IL-4 and IL-17 A induced by CCl₄ treatment, while promoted IFN-γ expression. Finally, the transcription factors ROR-γt and GATA3 were decreased, while T-bet was increased after YGL treatment. These results suggested that YGL attenuated CCl₄-induced hepatic fibrosis by accelerating the extracellular matrix degradation, blocking the TGF-β1/Smad signaling pathway and modulating the balance among IL-4, IL-17 A and IFN-γ, demonstrating YGL protective effect and its potential mechanisms in treating liver fibrosis.