Abstract
Berberine has demonstrated efficacy in alleviating experimental colitis in vivo and in vitro. However, the anti-colitis mechanisms of berberine that enable it to promote intestinal barrier function in vivo remain unclear. The present study aimed to evaluate the effect of berberine on intestinal epithelial barrier function, expression of tight junction proteins and the levels of inflammatory and oxidative stress factors in the intestinal mucosa of dextran sulfate sodium (DSS)-induced colitis mice. Berberine (100 mg/kg) was administered for five days to mice with established colitis, induced by administration of DSS (3% w/v) for six days. Intestinal barrier function and the presence of proinflammatory factors, oxidative stress and active signaling pathways in the colon were determined principally by western blotting and reverse transcription-quantitative polymerase chain reaction. It was observed that berberine reduced weight loss, shortening of the colon and colon damage in DSS-colitis mice. In addition, berberine significantly inhibited the increase of fluorescein isothiocyanate-dextran in serum and the decrease of zonula occluden-1 (also known as tight junction protein-1), occludin and epithelial cadherin expression in colonic tissue, relative to a DSS-treated control group. Berberine also significantly inhibited the expression of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α mRNA and phosphorylation of signal transducer and activator of transcription 3. Furthermore, berberine reduced the levels of myeloperoxidase and increased the levels of superoxide dismutase and catalase in colon and serum samples relative to the control group. The expression of cluster of differentiation 68 in the colon of colitis mice was also reduced by berberine. Collectively, these data suggest that berberine alleviates colitis principally by improving intestinal barrier function and promoting anti-inflammatory and antioxidative stress responses. In turn these effects inhibit macrophage infiltration into the colon and thus may be central to the anti-colitis activity of berberine.