Oxidative stress, apoptosis, and cell cycle arrest are induced in primary fetal alveolar type II epithelial cells exposed to fine particulate matter from cooking oil fumes.

Epidemiological studies demonstrate a linkage between morbidity and mortality and particulate matter (PM), particularly fine particulate matter (PM2.5) that can readily penetrate into the lungs and are therefore more likely to increase the incidence of respiratory and cardiovascular diseases. The present study investigated the compositions of cooking oil fume (COF)-derived PM2.5, which is the major source of indoor pollution in China. Furthermore, oxidative stress, cytotoxicity, apoptosis, and cell cycle arrest induced by COF-derived PM2.5 in primary fetal alveolar type II epithelial cells (AEC II cells) were also detected. N-acetyl-L-cysteine (NAC), a radical scavenger, was used to identify the role of oxidative stress in the abovementioned processes. Our results suggested that compositions of COF-derived PM2.5 are obviously different to PM2.5 derived from other sources, and COF-derived PM2.5 led to cell death, oxidative stress, apoptosis, and G0/G1 cell arrest in primary fetal AEC II cells. Furthermore, the results also showed that COF-derived PM2.5 induced apoptosis through the endoplasmic reticulum (ER) stress pathway, which is indicated by the increased expression of ER stress-related apoptotic markers, namely GRP78 and caspase-12. Besides, the induction of oxidative stress, cytotoxicity, apoptosis, and cell cycle arrest was reversed by pretreatment with NAC. These findings strongly suggested that COF-derived PM2.5-induced toxicity in primary fetal AEC II cells is mediated by increased oxidative stress, accompanied by ER stress which results in apoptosis.