Protective effect of acidic polysaccharide from Schisandra chinensis on acute ethanol-induced liver injury through reducing CYP2E1-dependent oxidative stress

Schisandra chinensis is a well-known traditional Chinese medicine used mainly as a recipe for hepatoprotection. Modern researches have revealed that the hepatoprotection is related to its lignans and crude polysaccharide. In this study, we examined the effect and mechanism of Schisandra chinensis acidic polysaccharide (SCAP) on the liver injury induced by ethanol.SCAP was extracted with water extraction and ethanol precipitation. Liver injury models of both mice and HepG2 cells were produced by ethanol. The liver index, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in serum of the mice and cell culture supernatant were examined; HE staining was performed for observing pathological changes of liver. The malondialdehyde (MDA) level and superoxide dismutase (SOD) activities in serum, liver tissue and HepG2 cells, and triglyceride (TG) content in liver tissue were tested. Western blot was conducted to determine cytochrome P450 2E1 (CYP2E1) expression in liver tissue of mice and HepG2 cells.SCAP significantly reduced serial AST and ALT levels in the injuried liver and HepG2 cells induced by ethanol and also decreased TG level in the liver tissue. SCAP also obviously improved the hepatopathological changes and decreased MDA level as well as increased SOD activities in the serum, liver tissue and HepG2 cells induced by ethanol. Furthermore, Western blot analysis indicated that SCAP significantly inhibited the upregulation of CYP2E1 protein.SCAP has a protective effect on ethanol-induced liver injury in mice and cells, and the mechanism underlying may be via inhibiting the expression of CYP2E1 protein and then alleviating oxidative stress injury induced by ethanol.