Abstract:This paper aimed to study the antioxidative effect of intracellular polysaccharides from Agaricus bitorquis（Quél.）Sacc.on oxidative stress in mice.The mice were randomly divided into five groups：intracellular polysaccharide low-dose group[25 mg/（kg·d）]，medium-dose group[50 mg/（kg·d）]，and high-dose group[100 mg/（kg·d）]，blank control group[distilled water，100 mg/（kg·d）]and positive control group[Hongjingtian capsules，200 mg/（kg·d）].They were given corresponding liquid by gavage for consecutive 35 days.The relevant physiological and biochemical indexes of mice were measured under compensatory metabolic condition.The intracellular polysaccharide low-，medium-and high-dose groups were compared with blank control group and positive control group to explore the relief and effect of intracellular polysaccharide from A.bitorquis on oxidative stress in mice.The results were as follows：Compared with the conditions in blank control group，the exhaustion swimming time and hypoxic survival time of mice in the low-，medium-，and high-dose groups was prolonged（P<0.01，P<0.05）.The content of malondialdehyde in the liver of mice was decreased（P<0.01），and the activities of superoxide dismutase and catalase in antioxidant enzymes were increased（P<0.01）in the low-，medium-and high-dose groups.The activities of glutathione peroxidase in the low-and medium-dose groups（P<0.05）and high-dose group（P<0.01）were elevated.Serum content of urea nitrogen，concentration of blood lactic acid，activity of lactate dehydrogenase，and content of NO in brain tissue of mice in the low-，medium-and high-dose groups were reduced（P<0.05）.Compared with the conditions in positive control group，the exhaustion swimming time was prolonged in the medium-and high-dose groups（P<0.05，P<0.01），and the hypoxic survival time in the two groups was also prolonged（P<0.05）.The content of malondialdehyde in the medium-and high-dose groups was lowered（P<0.05，P<0.01）.There was no significant difference in the activity of superoxide dismutase in the low-，medium-，and high-dose groups，while elevation was observed in the activity of catalase in medium-and high-dose groups（P<0.05），and the activity of glutathione peroxidase in these two groups（P<0.05，P<0.01）.The content of urea nitrogen in the medium-and high-dose groups was down-regulated（P<0.05，P<0.01），and the concentration of blood lactic acid in the high-dose group was down-regulated（P<0.01）.The activity of lactate dehydrogenase and the content of NO in brain tissue of mice in medium-and high-dose groups were decreased（P<0.01）.The antioxidant effect of intracellular polysaccharide high-dose group was better than that of low-and medium-dose groups，revealing a dose dependent manner.In conclusion，intracellular polysaccharides could reduce oxidative stress injury by enhancing the antioxidant defense mechanism，boost the compensatory metabolic level of the organism under oxidative stress，and improve the antioxidant stress ability of the organism.