Abstract:

Objective To investigate the improvement effect of Phellinus igniarius acidic polysaccharide（PIP） on liver fibrosis in the mice induced by bile duct ligation （BDL）， and to clarify its possible mechanism. Methods A total of sixty 4-week-old male C57/BL6 mice were randomly divided into control group， model group， positive drug group，and PIP group，with 15 mice in each group. The mice in control group only received the passed surgical line without ligation around the common bile duct， and the bile duct of mice in model group， postive drug group and PIP group were ligated. After administration for 3 weeks， the blood was taken from eyeball 12 h after the last administration， and the mice were sacrificed. The body weights and liver weights of mice were weighed， and the liver index was calculated. Microplate method was used to determine the levels of alanine aminotransferase （ALT） and aspartate aminotransferase （AST） in serum of the mice in various goups； the levels of type Ⅲ procollagen （PC Ⅲ） and cellagen type Ⅳ（Col Ⅳ） in serum were determined by double antibody sandwich method. HE staining and Sirius red staining were used to observe the pathomorphology and fibrosis degrees of liver tissue of the mice in various groups； the activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） and the levels of malondialdehyde （MDA）and glutathione （GSH） in liver tissue of the mice in various groups were determined. The expression levels of nuclear factor-E2 related factor （Nrf2）， heme oxygenase-1 （HO-1） and quinone oxidoreductase 1 （NQO1） proteins in liver tissue of the mice in various groups were detected by Western blotting method. Results Compared with control group，the body weight of the mice in model group had no significant difference（P>0.05），and the liver weight and liver index were increased（P<0.05）；compared with model group， the body weight of the mice in PIP group had no significant change（P>0.05）， and the liver weight and liver index were decreased（P<0.05）.The HE staining results showed no abnormalities in liver tissue of the mice in control group；the liver lobular structure was destroyed and focal liquefied hepatic necrosis and more inflammatory cell infiltration were seen in liver tissue of the mice in model group；compared with model group， the necrosis degrees of liver tissue of the mice in positive drug group and PIP group were significantly reduced， and the infiltration of inflammatory cells was reduced. The Sirius red staining results showed that compared with control group，the content of collagen fibers in liver tissue of the mice in model group was significantly increased；compared with model group，the content of collagen fibers in liver tissue of the mice in PIP group was significantly decreased.Compared with control group，the ALT and AST levels in serum of the mice in model group were increased（P<0.01），PC Ⅲ and Col Ⅳ levels were increased（P<0.05）， the activities of SOD and GSH-Px were significantly decreased（P<0.01），and the levels of MDA and GSH were significantly increased（P<0.05 or P<0.01）； compared with model group， the levels of ALT and AST in serum of the mice in positive drug group and PIP group were significantly decreased （P<0.01）， the levels of PC Ⅲ and Col Ⅳ were significantly decreased （P<0.05 or P<0.01）， the activities of SOD and GSH-Px in liver tissue of the mice were increased （P<0.05）， and the levels of GSH and MDA were decreased （P<0.05）.The Western blotting results showed that compared with control group，the expression levels of Nrf2，HO-1，and NQO1 proteins in liver tissue of the mice in model group were decreased （P<0.05）；compared with model group， the expression levels of Nrf2，HO-1，and NQO1 proteins in liver tissue of the mice in PIP group were significantly increased （P<0.05 or P<0.01）. Conclusion PIP can improve the liver fibrosis in the mice caused by BDL， and its mechanism may be related to reducing the level of liver oxidative stress and regulating the expression levels of Nrf2， HO-1 and NQO1 proteins in Nrf2 / HO-1 signaling pathway.

Key words: Phellinus igniarius acid polysaccharides, Liver fibrosis, Bile duct ligation, Nuclear factor-E2 related factor, Heme oxygenase-1