Apium graveolens L. alleviates acute lung injury in human A-549 cells by reducing NF-κB and NLRP3 inflammasome signaling

Background: Apium graveolens L. (celery) is a dietary vegetable with anti-inflammatory properties. It has the potential to treat acute lung injury (ALI) caused by COVID-19 or other diseases. Objective: To investigate the effects of Apium graveolens water extract (AGWE) on ALI in human lung A-549 cells induced by lipopolysaccharide (LPS). Materials and methods: A-549 cells were treated with AGWE for 24 h and then stimulated with 10 mu g/mL LPS for another 24 h. The effects of AGWE on cell viability, the inflammatory response, oxidative stress, and apoptosis and their regulatory factors, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa B), and NLR family pyrin domain containing 3 (NLRP3) inflammasome signaling activation were analyzed. Results: Treatment with 5-50 mu g/mL AGWE reversed the decrease in cell viability caused by LPS (p < 0.05). AGWE can reduce interleukin (IL)-1 beta, IL-6, IL-18, and TNF-alpha levels; their EC50 values are 61.4, 65.7, 37.8, and 79.7 mu g/mL, respectively. AGWE can reduce reactive oxygen species and thiobarbituric acid reactive substances in A-549 cells induced by LPS. AGWE also reduced the levels of apoptosis (EC50 of 74.8 mu g/mL) and its regulators (Bid; Caspase-9, -8, and -3; Bax) and increased the levels of the mitochondrial membrane potential in A-549 cells induced by LPS. AGWE can also decrease the protein levels of NLRP3 and Caspase-1 and the activation of NF-kappa B signaling in A-549 cells induced by LPS. Conclusions: These results show that 10 and 50 mu g/mL AGWE can reduce the acute inflammation induced by LPS by reducing NF-kappa B and NLRP3 inflammasome signaling and mitochondria-dependent apoptosis pathways.