Abstract: The present study was conducted to investigate the relieving effect of fucoidan on oxidative stress in rats.A total of 28 eight-week-old male SD rats were divided into three groups:control group (n=10) injected intraperitoneally with saline and feeding basal diet,oxidative stress group (n=9) injected intraperitoneally with 10 mg/kg BW diquat and feeding basal diet,fucoidan combined with oxidative stress treatment group (n=9) injected intraperitoneally with 10 mg/kg BW diquat and feeding diet supplemented with 250 mg/kg fucoidan.On the twelfth day of the trial,rats in oxidative stress and fucoidan combined with oxidative stress treatment groups were intraperitoneally injected diquat to establish oxidative stress model.At the end of the trial,the blood,liver and spleen tissue samples were collected.The results showed that dietary fucoidan relieved the increase of serum aspartate aminotransferase (AST) activity and decreased hepatic malondialdehyde (MDA) content of rats,and reversed the down-regulation of hepatic nuclear factor erythroid 2-related factor 2 (Nrf2),superoxide dismutase 2 (SOD2) and glutathione peroxidase (GPx) gene expression induced by oxidative stress,and improved the total antioxidant capacity (T-AOC) and GPx activity.In addition,dietary fucoidan reversed the down-regulation of splenic Nrf2 and GPx gene expression of rats induced by oxidative stress,and increased the T-AOC and activities of SOD and GPx.In conclusion,dietary fucoidan can alleviates oxidative stress in rats through its antioxidant activity via Nrf2 pathway.

Key words: fucoidan, oxidative stress, antioxidase, Nrf2, rats