Fucoidan from Stichopus chloronotus relieved DSS induced ulcerative colitis through inhibiting intestinal barrier disruption and oxidative stress

Intestinal barrier disruption and oxidative stress are the major pathological features during the ulcerative colitis (UC). The present research aimed to explore the amelioration property of fucoidan of Stichopus chloronotus (Fuc-Sc) against dextran sulfate sodium (DSS) resulted UC. The findings from our study suggest that treating with Fuc-Sc improved the integrity of the Caco-2 monolayer through raising its TEER value, reducing LDH release, promoting the tight junction proteins (TJs) in Caco-2 cells, and shielding the cells from decreases of these proteins caused by H2O2. Besides, Fuc-Sc activated Nrf2/HO-1 pathway to facilitate the antioxidant activities of Caco-2 cells under oxidative stress through elevating the SOD and GSH, and reducing LDH and MDA. Furthermore, oral administration of Fuc-Sc attenuated DSS resulted body weights decrease, DAI score increase, colon length decrease, and structural damage of colon tissue. Fuc-Sc also promoted the barrier function and suppressed oxidative injury via activation of Nrf2/HO-1 signal pathway. Collectively, this research provided the theoretical foundation for fucoidan as a promising functional food for colitis.