Indirubin, a Constituent of the Chinese Herbal Medicine Qing-Dai, Attenuates Dextran Sulfate Sodium-induced Murine Colitis.

Background: Indirubin, a constituent of the Chinese herbal medicine "Qing-Dai," has anti-cancer and anti-inflammatory activities. We aimed to evaluate the efficacy of indirubin for ameliorating colonic inflammation in a mouse model of inflammatory bowel disease.

Methods: Mice with dextran sulfate sodium (DSS)-induced acute and chronic colitis were treated with indirubin in their diet. Clinical and histologic changes were evaluated. In addition, colon levels of interleukin-6, a critical pro-inflammatory mediator, was detected by enzyme-linked immunosorbent assay.

Results: In the model of acute colitis, indirubin treatment improved the loss of body weight. Histology of colonic tissue revealed that indirubin treatment improved the histology grading of colitis ( = 0.02), the extent of submucosal fibrosis ( = 0.018), the number of mucosal toluidine blue-positive cells ( = 0.004) and colon length ( = 0.01). In the model of chronic colitis, indirubin treatment had no significant effect on pathologic findings except for colon length ( = 0.003). However, indirubin administration significantly reduced colon levels of interleukin-6 in the chronic-colitis model ( = 0.001).

Conclusion: Our study clearly showed that oral intake of indirubin can improve murine DSS-induced colitis (which mimics human inflammatory bowel disease).