Melatonin Ameliorates Apoptosis of A549 Cells Exposed to Chicken House PM2.5: A Novel Insight in Poultry Production

Abstract

The particulate matter 2.5 (PM2.5) from the chicken production system can cause lung injury and reduce productivity through prolonged breath as it attaches large amounts of harmful substances and microbes. Melatonin has acted to regulate physiological and metabolic disorders and improve growth performance during poultry production. This research would investigate the apoptosis caused by chicken house PM2.5 on lung pulmonary epithelial cells and the protective action of melatonin. Here, the basal epithelial cells of human lung adenocarcinoma (A549 cells) were subjected to PM2.5 from the broiler breeding house to investigate the apoptosis induced by PM2.5 as well as the alleviation of melatonin. The apoptosis was aggravated by PM2.5 (12.5 and 25 μg/mL) substantially, and the expression of Bcl-2, Bad, Bax, PERK, and CHOP increased dramatically after PM2.5 treatment. Additionally, the up-regulation of cleaved caspase-9 and cleaved caspase-3 as well as endoplasmic reticulum stress (ERS)-related proteins, including ATF6 and CHOP, was observed due to PM2.5 exposure. It is worth noting that melatonin could support A549 cells’ survival, in which reduced expression of Bax, Bad, cleaved caspase-3, and cleaved caspase-9 appeared. Concurrently, the level of malondialdehyde (MDA) was down-regulated and enhanced the intracellular content of total superoxide dismutase (T-SOD) and catalase (CAT) after treatment by PM2.5 together with melatonin. Collectively, our study underlined that melatonin exerted an anti-apoptotic action on A549 cells by strengthening their antioxidant capacity.