Chicoric acid alleviates lipopolysaccharide-induced acute lung injury in mice through anti-inflammatory and anti-oxidant activities.

Acute lung injury (ALI) is a severe clinical disease with high mortality rates. Chicoric acid (CA), an active component extracted from traditional Chinese medicine, was suggested to have anti-inflammatory and anti-oxidant activities. Inflammation and oxidative damage are implicated in the pathogenesis of ALI. In this study, we explored the protection effect of CA on LPS-induced ALI, and further discussed the possible molecular mechanisms. The results showed that CA could significantly improve the histological changes of LPS-induced acute lung injury. In addition, CA not only decreased LPS-stimulated protein leakage and lung wet/dry ratio but also reduced inflammatory cell infiltration, myeloperoxidase (MPO) activity and the generation of pro-inflammatory cytokines in bronchoalveolar lavage fluid (BALF). Meanwhile, CA lessened the reactive oxygen species (ROS) generation, and malondialdehyde (MDA) formation, and decreased glutathione (GSH) and superoxide dismutase (SOD) depletion, which were caused by LPS challenge. Furthermore, CA dramatically inhibited LPS-stimulated MAPK and NLRP3 activation and increased the expression of NAD (P) H: quinone oxidoreductase (NQO1), and dismutase (SOD), glutamate-cysteine ligase catalytic/modifier (GCLC/GCLM) subunit and heme oxygenase-1 (HO-1), as well as its upstream genes nuclear factor-erythroid 2-related factor 2 (Nrf2), which might be central to the protective effects of CA. In conclusion, these data indicated that the protective effects and mechanisms of CA on LPS-induced ALI and provided new insights for its application.