Interleukin 6 inhibition by triptolide prevents inflammation in a mouse model of ulcerative colitis

The present study aimed to assess interleukin (IL)-6 expression in a murine model of ulcerative colitis (UC) induced by dextran sulfate sodium (DSS) and its potential association with the anti-colitis effects of triptolide (TL). Serum IL-6 levels were measured by ELISA. IL-6 gene expression levels in colonic mucosa specimens were assessed by reverse-transcription quantitative PCR and protein expression was evaluated by western blot analysis and immunohistochemistry. The expression of IL-6 was weak in mucosa specimens from normal control animals and upregulated in DSS-induced mice. In model mice treated with TL (0.4 and 0.6 mg/kg), dexamethasone or mesalazine, IL-6 expression was significantly reduced compared with that in model mice treated with normal saline or propylene glycol (P<0.05), while TL at 0.2 mg/kg did not elicit any significant inhibitory effect. There was no significant difference among TL (0.4 mg/kg and 0.6 mg/kg), mesalazine and dexamethasone treatments (P>0.05) in terms of IL-6 expression or histological score. The results of the present study indicated that IL-6 was overexpressed in a mouse model of UC and was involved in disease progression. In addition, TL exerted therapeutic effects in UC through inhibition of IL-6 expression.