Abstract: Objective:To investigate the protective effect of purslane polysaccharide on CCl₄ induced acute liver injury in mice. Methods:Establishment of acute liver injury model in mice by intraperitoneal injection of carbon tetrachloride(CCl₄). 60 mice were randomly divided into normal group,model group,biphenyl diester group(200 mg/kg·d),purslane polysaccharide low,medium and high dose group(1.5,3,6 g/kg/d),and were given continuous gavage for 7 days. In addition to the normal mice,other mice in each group were injected with 0.2% CCl₄ peanut oil 10 mL/kg intraperitoneally. Calculation of liver index,and the levels of AST,ALT and ALP in serum and the activities of MDA,SOD,GSH and GSH-Px in liver were measured by ELISA,HE staining to observe the pathological changes of liver tissue,and detection of Nrf-2 and HO-1 protein expression in liver by Western Blot. Results:Comparison with normal group,purslane polysaccharide low-dose group could significantly reduce the content of serum ALP(P<0.05). At the same time,SOD level and Nrf-2 protein expression level in liver homogenate were significantly increased(P<0.05). In the medium dose group,the liver index,AST and ALT contents in serum and MDA level in liver homogenate were significantly decreased(P<0.05),while the GSH and GSH-Px levels in liver homogenate were significantly increased(P<0.05),ALP content in serum and SOD level and Nrf-2 and HO-1 protein expression in liver homogenate were significantly increased(P<0.01). Purslane polysaccharide high-dose group could significantly reduce the content of AST in serum(P<0.05),liver index,significantly increase the levels of GSH and GSH-Px in liver tissue homogenate(P<0.05),significantly reduce the contents of AST,ALP and MDA in serum(P<0.01),and significantly increase the levels of SOD and Nrf-2 and HO-1 protein in liver tissue homogenate(P<0.01). In addition,the results of liver histopathology showed that purslane polysaccharide could reduce the pathological damage of liver caused by CCl₄. Conclusion:The protective effect of purslane polysaccharide on CCl₄ induced acute liver injury in mice is related to the activation of Nrf-2/HO-1 signal pathway.