Sodium Ferulate Attenuates Oxidative Stressvia Suppressing NALP3 Inflammasome and ERK Signal Pathway

Objective Study the gene and protein expression of NACHT-PYD-containing protein 3 (NALP3) inflammasome and extracellular regulated protein kinase (ERK), the intervention effects of sodium ferulate (SF) in human lung epithelial cells A549 under oxidative stress, and to investigate the possible mechanism. Methods Human lung epithelial cells A549 cultured in vitro were divided into 6 groups, including control group, H₂O₂ (200 μmol/L) group, SF group (400 μg/mL), caspase-1 blockers (Z-VAD) group (Z-VAD 20 μmol/L+H₂O₂ 200 μmol/L), ERK blockers (PD98059) group (PD98059 50 μmol/L+H₂O₂ 200 μmol/L), and SF+H₂O₂ group (SF 400 μg/mL+H₂O₂ 200 μmol/L). Fluorescent quantitative real-time PCR (qRT-PCR) was performed to detect the mRNA levels of caspase-1 and NALP3, the expression of caspase-1, NALP3, phosphorylated ERK p-ERK, ERK protein were evaluated by Western blot. The level of interleukin-1 beta (IL-1β) were detected by ELISA. Results Compared with the control group,H₂O₂ not only increased the mRNA and protein expression levels of caspase-1 and NALP3 and the protein expression levels of p-ERK/ERK, but also enhanced the secretion of IL-1β in human lung epithelial cells A549 (P <0.05),while SF group showed no statistic significance of those indicators above (P >0.05). The Z-VAD group, the PD98059 group and the SF+H₂O₂ group resisted the effects of H₂O₂ on A549 cells by decreasing the mRNA and protein expressions of caspase-1 and NALP3,and the protein expression of p-ERK/ERK, as well as reducing the secretion of IL-1β (P < 0.05),when compared with the H₂O₂ group.Conclusion SF may reduce the expression of caspase-1, NALP3 and IL-1β by inhibiting ERK, so as to reduce the inflammation caused by oxidative stress.