Objective: To study the oxidative damage of PM2.5 in human embryonic stem cells (EBf-H9 cells), and to provide a theoretical basis for revealing the adverse health effects of PM2.5 and the potential mechanisms, and also to provide a new alternative cell model for PM2.5 risk assessment.
Methods: EBf-H9 cells were cultured with 0.00 (the constrast group) 3.91, 7.81, 15.63, 31.25, 62.50, 125.00 μg/cm(2) of PM2.5. CCK-8 kit was used to determine the survival rate of cells exposed to PM2.5 for 6 h. DCFH-DA probe was used to detect the total ROS content of cells exposed to PM2.5 for 1 h. The activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px), and the content of lipid peroxides such as malondialdehyde (MDA) in cells exposed to PM2.5 for 6 h were detected by using the commercial kits. ANOVA model analyzed the statistical significance from the different concentration group.
Results: The cytotoxicity results showed that the cell survival rate was decreased gradually with the increase of the concentrations of PM2.5, and the half inhibitory concentration (IC50) was 83.01 μg/cm(2). When the exposure concentration was 3.91, 7.81, 15.63, 31.25, 62.5 μg/cm(2), after exposure of PM2.5 1 h, the ROS florescence was 27.12±0.21, 54.03±0.50, 60.93±0.08, 61.36±1.00, 68.21±0.93, 78.27±1.26 (compared to control group 27.12±0.21, all P level<0.01). After exposure of PM2.5 6 h, the activities of T-SOD was (9.78±0.28), (8.59±0.22), (8.90±0.33), (7.46±0.71), (4.21±0.17) U/mg protein (F=98.881, compared to control group (11.77±0.63) U/mg protein, all P level<0.01). The activities of GSH-Px was (181.59±3.65), (153.33±1.69), (168.74±2.22), (81.56±0.56), (48.62±2.13) U/mg protein (compared to control group (273.90±6.50) mU/mg protein, all P level<0.01). And the content of MDA was (0.38±0.03), (0.43±0.09), (0.47±0.09), (0.65±0.10), (0.70±0.12) nmol/mg protein (compared to control group (0.27±0.02) nmol/mg protein, all P level<0.05).
Conclusion: PM2.5 exposure can decrease EBf-H9 cells viability, and improve the levels of lipid peroxidation. It may be due to induce EBf-H9 cells to increase the production of ROS and to make the cells appear oxidative stress, which lead to oxidative damage to cells. The present study reveals the mode of action of PM2.5 in terms of oxidative damage to EBf-H9 cells. It is also indicated that the cells may be a new alternative cell model for PM2.5 risk assessment.