Water soluble and insoluble components of PM_2.5 and their functional cardiotoxicities on neonatal rat cardiomyocytes in vitro

A growing number of epidemiological surveys show that PM_2.5 is an important promoter for the cardiovascular dysfunction induced by atmospheric pollution. PM_2.5 is a complex mixture of solid and liquid airborne particles and its components determine the health risk of PM_2.5to a great extent. However, the individual cardiotoxicities of different PM_2.5 fractions are still unclear, especially in the cellular level. Here we used the neonatal rat cardiomyocytes (NRCMs) to evaluate the cardiac toxicity of PM_2.5 exposure. The cytotoxicities of Total-PM_2.5, water soluble components of PM_2.5 (WS-PM_2.5) and water insoluble components of PM_2.5 (WIS-PM_2.5), which include the cell viability, cell membrane damage, reactive oxygen species (ROS) generation, were examined with NRCMs in vitro. The results indicated that Total-PM_2.5 or WIS-PM_2.5 exposure significantly decreased the cell viability, induced the cell membrane damage and increased the ROS level in NRCMs at concentrations above 50 µg/mL. However, WS-PM_2.5 exposure could induce the cytotoxicity on NRCMs until the concentration of WS-PM_2.5 was raised to a higher concentration (75 µg/mL). Furthermore, the DNA damage was detected in NRCMs after 48 h of exposure with Total-PM_2.5, WS-PM_2.5 or WIS-PM_2.5 (75 µg/mL) and the adverse effects on mitochondrial function and action potentials of NRCMs were detected only both in the Total-PM_2.5 and WIS-PM_2.5 treatment group. In summary, our project not only estimates the risk of PM_2.5 on cardiac cells but also reveal that Total-PM_2.5 and WIS-PM_2.5 exposure were predominantly associated with the functional cardiotoxicities in NRCMs.