Artesunate improves DDC-induced cholestatic liver fibrosis through PI3K/Akt/mTOR signaling pathway in mice

To explore the effect and molecular mechanism of artesunate（ART）on cholestatic liver fibrosis induced by 3, 5-diethoxycarbonyl-1, 4-dihydro-2, 4, 6-collidine（DDC）.

8-week-old male C57BL/6J mice（n=24）were randomly divided into 3 groups: the control group（n=6）, the 0.1% DDC group（n=9）and the 0.1% DDC+ART group（n=9）. Mice have been fed with diet containing 0.1% DDC for 2 weeks to establish cholestatic mouse model, and ART was given intramuscular injection（30.0 mg/kg）once a day in the 0.1% DDC+ART group. The indicators of liver injury in serum of mice were detected. HE staining and Sirius red staining were performed, and histopathological scores were obtained according to Scheuer scoring system. RT-qPCR was used to detect the levels of α-SMA, Col1a1, Col1a2 and Tgfβ1 in mouse liver. Hydroxyproline（HYP）content was detected with HYP detection kit. LX2 cells were treated with TGF-β combined with ART, and the proteins related to PI3K/Akt/mTOR pathway were detected by Western blot assay. The expression of α-SMA, hepatic stellate cell（HSC）activation marker, was detected after ART and pathway inhibitors were used to treated with LX2 cells.

ART significantly ameliorated DDC-induced cholestatic liver injury and liver fibrosis（P<0.05）. ART markedly decreased the levels of ALT, AST, ALP and TBA in serum of mice（P<0.05）. ART inhibited the mRNA expression of α-SMA, Col1a1, Col1a2 and Tgfβ1, and reduced the content of HYP in liver tissues of mice with cholestasis（P<0.05）. In addition, ART obviously inhibited TGF-β-induced activation of PI3K/Akt/mTOR pathway in LX2 cells（P<0.05）. PI3K/Akt/mTOR signaling pathway inhibitors enhanced the inhibitory effect of HSC activation induced by TGF-β（P<0.05）.

ART observably improves DDC-induced cholestatic liver fibrosis, and it can inhibit HSC activation by regulating PI3K/Akt/mTOR signaling pathway, thus exerting anti-fibrosis effect.