Protection against Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice by Neferine, A Natural Product from Nelumbo nucifera Gaertn.

Ulcerative colitis (UC) is a long-lasting inflammatory disease of the colon. Epidemiological studies showed that the prevalence and incidence of UC are increasing worldwide in recent years. Neferine is a natural alkaloid isolated from Nelumbo nucifera Gaertn that exerts a variety of biological activities. This study was designed to evaluate the protective effect of neferine on dextran sulfate sodium (DSS)-induced experimental UC in mice.In this experimental study, 4% DSS was used to induce a mice model of UC. Neferine (5 and 10 mg/kg) was administered by intraperitoneal injection (ip). Clinical symptoms and disease activity index (DAI) scores were recorded and calculated. Pathological changes of colon tissues were detected by Hematoxylin and Eosin (H and E) staining. The levels of inflammatory mediators were detected by ELISA kits. Western blotting and immunohistochemical analysis were used for the evaluation of protein expressions.Neferine treatment significantly alleviated DSS-induced UC by inhibiting weight loss, decreasing DAI scores, and alleviating the pathological changes in colon tissues. Furthermore, neferine significantly decreased serum levels of pro-inflammatory cytokines including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and IL-6 and increased serum levels of anti-inflammatory cytokine IL-10. The increased myeloperoxidase (MPO) activity and nitric oxide (NO) in colon tissues were also inhibited. In addition, neferine significantly down-regulated inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and intercellular cell adhesion molecule-1 (ICAM-1) expression in colon tissues.These results provided evidence that neferine could protect against DSS-induced UC symptoms in an experimental mice model. This effect might be mediated through inhibition of inflammation.