大气PM2.5对大鼠心肌细胞的毒性作用

为评估大气PM_2.5及其不同组分对心肌细胞H9C2的毒性作用，探讨PM_2.5对心血管系统产生毒性作用的关键组分，将前期采集并制备的PM_2.5完全颗粒物、PM_2.5水溶性组分、PM_2.5脂溶性组分和PM_2.5单纯颗粒物以不同质量浓度对H9C2细胞染毒.用MTS法在染毒6、10、24、48、72 h后测定细胞活力；根据细胞活力测定结果，选用较低染毒浓度（10 μg/mL），用相关试剂盒测定染毒24 h后胞内和上清液中LDH（乳酸脱氢酶）和SOD（超氧化物歧化酶）活力，ELISA及RT-qPCR法测定炎性因子IL-6和TNF-α表达量，AP位点计数法测定细胞DNA损伤情况.结果表明:颗粒物成分（PM_2.5完全颗粒物和PM_2.5单纯颗粒物）对H9C2细胞表现出强烈的生长抑制作用，50 μg/mL及以上染毒浓度组在染毒时间≥ 24 h时细胞可能已经全部死亡，而可溶性成分（PM_2.5水溶性组分和PM_2.5脂溶性组分）对H9C2细胞生长表现为极弱或无生长抑制作用，仅400 μg/mL的PM_2.5脂溶性组分始终对细胞生长表现出抑制作用；各组分样本都在一定程度上造成了H9C2细胞损伤，降低了胞内LDH和SOD活性；PM_2.5完全颗粒物和PM_2.5脂溶性组分在造成炎性损伤方面的作用较为明显.研究显示，颗粒物组分对H9C2细胞致死作用显著，相对而言，PM_2.5完全颗粒物表现出的毒性作用最强且最全面. 

Toxic Effects on Rat Cardiac Myocytes from Atmospheric PM2.5 Particles

To investigate the toxic effects of atmospheric PM_2.5 and its different fractions on the rat cardiac myocyte H9C2, and explore the key fractions causing toxic effects on the cardiovascular system, the prepared samples, including the original PM_2.5 particles (designated OPP_2.5), water-soluble particles in PM_2.5 (designated WPP_2.5), the fat-soluble particles in PM_2.5 (designated FPP_2.5) and the pure particulate fractions of PM_2.5 (designated PPP_2.5), were exposed to H9C2 cells at different concentrations. The MTS method was used to detect the cell viability at 6, 10, 24, 48 and 72 h post-treatment, and according to the detected results, a low PM concentration (10 μg/mL) was selected for the following experiments. Firstly, appropriate kits were used to detect the activities of lactate dehydrogenase and superoxide dismutase at 24 h post-treatment; secondly, ELISA and RT-qPCR were employed to detect the production of inflammatory cytokines IL-6 and TNF-α, and finally, AP-site counting was conducted to determine the level of intracellular DNA damage at 24 h post-treatment. The results demonstrated that the insoluble samples (OPP_2.5 and PPP_2.5) showed strong inhibitory effects toward cell growth, and the sample groups with particle concentrations of 50 μg/mL and above may have killed all H9C2 cells for exposure times of more than 24 h; while the soluble samples (WPP_2.5 and FPP_2.5) showed very weak and even no inhibitory effects toward cell growth, and only FPP_2.5 at 400 μg/mL showed inhibitory effects from 6 h to 72 h post-treatment; all samples caused damage to H9C2 cells to some extent and decreased the activities of intracellular LDH and SOD; in addition, OPP_2.5 and FPP_2.5 played an evident role in inducing inflammatory injury in H9C2 cells. A conclusion can be reached that the insoluble samples of atmospheric PM_2.5 showed significant lethal effects toward H9C2 cells, and OPP_2.5 showed the strongest and the most comprehensive toxic effects on H9C2 cells.