[Animal modeling] - Experimental study on the adhesive and antioxidant effects of mussel mucin on ulcerative colitis in rats

  Objective To observe the effect of mussel mucin (MAP) on intestinal mucosa of rats with ulcerative colitis, and to explore its mechanism from the perspective of adhesion and antioxidation.

  Methods Thirty two SPF SD rats were randomly divided into normal group, model group, mesalazine group and mussel mucin group (0.6 mg/kg) with 8 rats in each group. The normal group was given ordinary drinking water, and the other groups were given 5% dextran sulfate (DSS) free water for 7 days to prepare the model of ulcerative colitis. They were administered daily 24 hours after the model was established. The daily disease activity index (DAI) and body weight changes of rats in each group were observed and recorded. Seven days after the drug was administered, the anatomical materials were taken, the length, weight, and intestinal weight ratio of rats in each group were recorded, and the general morphology (CMDI) and histopathology of colorectal mucosa were observed. The intestinal mucosa of rats was taken for in vitro test, and the effect of MAP on the adhesion and antioxidation of intestinal mucosa of rats was observed by nitro tetrazolium chloride blue (NBT) staining.

  Results Compared with the normal group, the DAI score of the model group increased significantly (P<0.05) and body weight decreased (P<0.05) from the fifth day of the experiment. The congestion, edema and ulcer formation of the intestinal mucosa, as well as the swelling and deformation of the colonic recess and the infiltration of a large number of inflammatory cells in the submucosal tissue were observed in the model group; Compared with the model group, the weight and colorectal length of rats in the mesalazine group and mussel mucin group increased (P<0.05), and the DAI score, intestinal weight ratio, CMDI score and histopathological score decreased (P<0.05). In the NBT experiment, the rectal mucosa of rats appeared blue staining, and the degree of blue staining was further deepened with time.

  Conclusion MAP can obviously improve the symptoms of ulcerative colitis model rats and repair the damage of intestinal mucosal barrier through its good adhesive and antioxidant effects on intestinal mucosa, which can provide a reliable experimental basis for the treatment of ulcerative colitis with MAP.