Pharmacological relevance: Ethyl pyruvate (EP), a potent reactive oxygen species scavenger, has been reported to contribute to the inflammatory process. However, the protective effect of ethyl pyruvate on Concanavalin A (Con A)-induced autoimmune hepatitis have not been explored. Thus, the aims of this study are to investigate both the effects of ethyl pyruvate and its mechanism of protection on Con A-induced autoimmune hepatitis in mice.
Materials and methods: Acute autoimmune hepatitis was induced by Con A (20 mg/kg) in Balb/C mice; ethyl pyruvate (40 mg/kg and 80 mg/kg) was administrated 1h prior to the Con A injection. At 3h, 6h and 24h post Con A injection, histological grading, proinflammatory cytokine levels and nuclear factor kappa B (NF-κB) activity were determined.
Results: Following Con A challenge, cytokines TNF-α, IL-2, IL-1β and IL-6 were expressed at 3h and 6h, and the level of HMGB1 significantly increased by 24h. Pretreatment with ethyl pyruvate ameliorated the pathological effects of Con A-induced autoimmune hepatitis and significantly decreased the levels of TNF-α, IL-2, IL-6 and IL-1β at 3h and 6h and the level of HMGB1 at 6h and 24h post injection. Ethyl pyruvate blocked the degradation of IκB α and IκB β and decreased the expression of NF-κB at 24h.
Conclusion: Taken together, these results indicated that ethyl pyruvate protected against Con A-induced autoimmune hepatitis by decreasing both early (TNF-α, IL-2, IL-1β and IL-6) and late (HMGB1) cytokine expression in mice. The reduction of HMGB1 may correlate with the amelioration of NF-κB activity.