OCLN and colitis: It is found that oral PLGA-RMP can inhibit the expression of IFN-γ and IL-6, upregulate the expression of IL-10, ZO-1 and occludin, adjust the metabolic disorder (up regulating the content of acetate, propionate and butyrate, reducing the diversity and richness of intestinal microbiota), repair intestinal barrier and finally prevent weight loss, reduce the DAI score, and promote the recovery of colon length in DSS-induced colitis mice.