Cytotoxicity induced by fine particulate matter (PM2.5) via mitochondria-mediated apoptosis pathway in human cardiomyocytes

Although the strongly causal associations were between fine particulate matter (PM2.5) and cardiovascular disease, the toxic effect and potential mechanism of PM2.5 on heart was poorly understood. Thus, the aim of this study was to evaluate the cardiac toxicity of PM2.5 exposure on human cardiomyocytes (AC16). The cell viability was decreased while the LDH release was increased in a dose-dependent way after AC16 exposed to PM2.5. The reactive oxygen species (ROS) generation and production of malondialdehyde (MDA) were increased followed by the decreasing in superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). The damage of mitochondria was observed by ultra-structural analysis and MMP measurement. The apoptotic rate of AC16 were markedly elevated which was triggered by PM2.5. In addition, the proteins involved in mitochondria- mediated apoptosis pathway were measured. The protein levels of Caspase-3, Caspase-9 and Bax were up-regulated while the anti-apoptotic protein, Bcl-2 was down-regulated after AC16 exposed to PM2.5. In summary, our results demonstrated that mitochondria-mediated apoptosis pathway played a critical role in PM2.5-induced myocardial cytotoxicity in AC16, which suggested that PM2.5 may contribute to cardiac dysfunction.