Chlorogenic acid ameliorated concanavalin A-induced hepatitis by suppression of Toll-like receptor 4 signaling in mice
Chlorogenic acid (CGA), one of the most abundant dietary polyphenolic compounds, has been reported to exhibit anti-inflammatory ability. However, the hepatoprotective effects and molecular mechanisms of CGA on concanavalin A (Con A)-induced hepatitis have not been explored. In the present study, we found that pretreatment with CGA dose-dependently inhibited the elevation of plasma aminotransferases and alleviated hepatic pathological damage as well as hepatocyte apoptosis in Con A-exposed mice. Additionally, CGA markedly suppressed the production of serum tumor necrosis factor (TNF)-α and interferon (IFN)-γ, alleviated the infiltration of hepatic macrophages, neutrophils, and activated CD4+ T lymphocytes in Con A-primed mice. Moreover, CGA downregulated Con A-induced hepatic expression of adhesion molecules (ICAM-1, VCAM-1 and ELAM-1) mRNA and protein, and inhibited Con A-activated Toll-like receptor (TLR) 4 signal molecules including TLR4, p-IRAK1, p-IκB, and p-p38. Finally, our results also showed that CGA exhibited a therapeutic effect, which CGA posttreatment improved hepatic damage at 1, 3, and 6 h after Con A. Taken together, these data suggested that CGA could effectively prevent mice from Con A-induced hepatitis, which might be through suppressing the activation of TLR4 signaling, downregulating the expression of adhesion molecules, and alleviating the infiltration and activation of hepatic leukocytes and the production of pro-inflammatory cytokines.