Objective:To investigate the anti-aging activity of Mytilus coruscus polysaccharide (MP) in aged rats.Methods:We established a 24-month natural aging rat model.Twenty model rats were divided into 4 groups,namely,the aging model group,Mytilus coruscus powder group (MCP 1 g/kg),high dose MP group (MP 400 mg/kg),and low dose MP group (MP 200 mg/kg).Five three-month-old rats served as young control.The Mytilus coruscus power solutions and MP solutions were given intragastrically on a daily basis for 90 days.The organ indices of the heart,liver,kidney,and spleen of rats were observed; the pathology of the hearts and livers was also observed.The levels of superoxidedismutase (SOD),glutatio-neperoxidase (GSH-Px),and malonaldehyde(MDA) in the serum and liver were determined; and the main serum parameters were also determined.Results:Compared with the aging model group,the heart and liver pathology had no obvious aging changes in the high dose MP group.The serum and liver SOD,GSH-Px levels were significantly higher in the high dose MP group than those in the aging model group (P<0.01); the MDA level was significantly lower than those in the aging model group (P<0.01).Conclusion:The Mytilus coruscus polysaccharide possess anti-aging activity,and the anitoxidative effect might be one of the mechanism for the anti-aging effect.