Polysaccharide from Gracilaria Lemaneiformis prevents colitis in Balb/c mice via enhancing intestinal barrier function and attenuating intestinal inflammation

This study explored the preventive effects of polysaccharide extracted from Gracilaria Lemaneiformis in mice with colitis induced by dextran sulfate sodium (DSS). FT-IR spectrum showed that SP was a typical sulfated polysaccharide (SP), which contained high content of S element in energy dispersive spectrometer (EDS) analysis. SP was mainly composed of (1 → 3)-linked glycosidic bonds. Our results showed that SP could improve physical conditions of mice via alleviating weight loss and appetite suppression. Besides, SP could decrease the content of endotoxin (ET), lipopolysaccharide binding protein (LBP) and the activity of myeloperoxidase in serum. Meanwhile, SP also suppressed the secretion of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) in colon tissue. These indicators showed that SP had ameliorated colitis symptoms. Furthermore, histological analysis indicated that SP could maintain healthy colonic microstructure including crypt, goblet cell and mucosal muscularis. Meanwhile, immunohistochemical results showed that tight junction proteins, including Claudin-1, ZO-1, and mucin (MUC-2) were promoted in colon with SP treatment. In conclusion, SP could enhance intestinal barrier, protect colonic microstructure and attenuate DSS-induced colonic injuries in mice, which suggested that SP could be a potentially functional component against colitis.