Protection of Sophocarpine on Colonic Barrier in DSS-induced Acute Colitis in Mice by Increasing Expression of HNF4α

Objective To investigate the possible protective effects of sophocarpine on mucosal injury and epithelial barrier disruption on dextran sulfate sodium(DSS)-induced acute colitis. Methods Male BALB/c mice were randomly divided into three groups. The mice in normal group were given normal water, and those in model and sophocarpinetreated groups were given 2.5% DSS for 6 d to induce acute colitis. Sophocarpine(30 mg/kg) was ip administered once daily during the study period. Severity of colitis was evaluated by disease activity index(DAI), histological injury and inflammatory cytokine production including tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1β), and monocyte chemoattractant protein-1(MCP-1). The colonic barrier disruption was assessed by testing the expression of junctional adhesion molecule-1(JAM-1), E-cadherin(E-CAD), and desmocollin-2(DSC-2) in colon mucosa. Expression of HNF4α in colon mucosa was detected by immunohistochemistry staining and real-time RT-PCR, respectively. Results Compared with normal group, DAI, colonic shortening, and histopathological injury in model group were elevated(P < 0.05), but reduced in sophocarpine-treated group(P < 0.05). Compared with model group, the m RNA expression of inflammatory cytokines(TNF-α, IL-1β, MCP-1) were obviously lower in sophocarpine-treated group(P < 0.05), while the cellular junction proteins(E-CAD, JAM-1, and DSC-2) were higher(P < 0.05). The expression of HNF4α at m RNA and protein levels was decreased significantly in model group, but increased apparently in sophocarpine-treated group. Conclusion Sophocarpine can enhance the expression of HNF4α, promote the expression of colonic intrecellular junctions, thus, maintain the integrity of the colonic barrier and inhibit the colitis process. We suggest that sophocarpine could enhance the production of cellular junction proteins to protect the intestinal barrier fuction, at least partly, in HNF4α-dependent pathway.