Protective Effects of Enteral Nutrition Supplemented with Crassostrea hongkongensis Polysaccharides Against 5-Fluorouracil-Induced Intestinal Mucosal Damage in Rats

Chemotherapeutics, including 5-fluorouracil (5-FU), often damage the intestinal mucosal barrier and cause intestinal mucositis (IM). Supplementation with immunoregulatory polysaccharides from Crassostrea hongkongensis has been shown to positively influence the effectiveness and toxicity of 5-FU. Therefore, we studied the effects of oyster polysaccharides on 5-FU-induced intestinal mucosal damage in rats. The C 30–60% ethanol-precipitated fraction of polysaccharides promoted IEC-6 cell proliferation and exhibited a maximal effect at a 0.0195 mg/mL concentration. Moreover, treatment with C 30–60% polysaccharide-based nutrition formula (OPNF) partially prevented the 5-FU-induced degenerative changes in the histology and ultrastructure of small intestinal mucosa. In addition, the endotoxin level of rats fed with 5-FU and OPNF decreased to the normal control level. Furthermore, the 5-FU-induced increase of proinflammatory cytokine interleukin (IL)-2 and the decrease of anti-inflammatory cytokine IL-10 level in the peripheral blood were significantly attenuated by OPNF administration. In conclusion, Oyster C 30–60% polysaccharides can ameliorate 5-FU-induced IM by partially preventing mucosal damage, reducing inflammation, and promoting immunity.