Repair effect of purple sweet potato anthocyanin on intestinal barrier injury in mice with ulcerative colitis induced by DSS

AIM To explore the repair effect of purple sweet potato anthocyanin on intestinal barrier injury of ulcerative colitis mice induced by dextrin sulfate sodium （DSS）. METHODS The mice were randomly divided into normal drinking group， DSS model group， different doses of purple sweet potato anthocyanin （12.5， 25， 50 and 75 mg/kg） groups， and 5-aminosalicylic acid （5-ASA） positive drug control group. Except using normal drinking water for control group， the mice in the other groups were treated with 2.5% DSS in drinking water for 7 days to induce the ulcerative colitis model. The mice in purple sweet potato anthocyanin treatment group and the 5-ASA positive drug control group were given the drug by intragastric gavage on the first day of modeling. The body weight of the mice and the hematocheziawere recorded every day. After continuous administration for 8 days， the mice in each group were killed and colon tissue was retained. Immunohistochemical technique （IHC） was used to detect the expression of tight junction protein ZO-1 and occludin and inflammatory factors tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in the colon of mice. The expression of mucin in goblet cells of colon tissue was observed by glycogen PAS staining. The protein expression of ZO-1， occludin， TNF-α were determined by Western blot， Sirius red staining was used to detect colonic fibrosis in mice. RESULTS Compared with control group， the disease activity index and histological injury of DSS model mice were significantly increased（P<0.01）. Compared with model group， the disease activity index scores of the mice in different dose groups of purple sweet potato anthocyanin were decreased. The expression and distribution of ZO-1 and occludin in colon tissues were increased， and the expression and distribution of TNF-α and IL-6 in colon tissues were decreased. Glycogen PAS staining showed a significant increase in the distribution and expression of mucin in goblet cells of colon tissues in the purple sweet potato anthocyanin treatment group. Sirius red staining also showed that the degree of fibrosis in the purple sweet potato anthocyanin treatment groups was lower than that in model group. CONCLUSION Purple sweet potato anthocyanins has therapeutic effect on ulcerative colitis in mice induced by DSS， mainly through up-regulating the expression of tight junction proteins ZO-1 and occludin， to protect the integrity of intestinal barrier， inhibiting the expression of inflammatory cytokines TNF-α and IL-6 and intestinal fibrosis， to suppress the development of colonic inflammation.