长春市冬季大气PM2.5对RAW264.7细胞毒性机制研究

目的研究长春市冬季大气PM2.5对小鼠单核巨噬细胞白血病细胞(RAW264.7细胞)的毒性作用。方法采用2016年11月16日至2017年3月18日期间基于空气质量指数的五级及以上雾霾天气采集的长春市大气PM2.5对RAW264.7细胞进行体外染毒,终浓度分别为0、50、100、200、400μg/ml。以四甲基偶氮唑盐比色法(MTT)检测细胞活力,用酶标仪测定胞内活性氧(ROS)、乳酸脱氢酶(LDH)释放量及Ca^2+浓度,并用流式细胞仪测定细胞凋亡率,用ELISA法检测肿瘤坏死因子(TNF-α)和白细胞介素-6(IL-6)含量。结果PM2.5染毒浓度为100、200、400μg/ml时,RAW264.7细胞存活率明显低于对照组,LDH、ROS水平和Ca^2+浓度明显高于对照组,TNF-α和IL-6含量明显高于对照组,细胞凋亡率亦随染毒浓度的增加而升高,差异均有统计学意义(P<0.05)。结论长春市冬季重污染大气PM2.5可使RAW264.7细胞产生炎症损伤和氧化应激,进而引起细胞凋亡。

Toxicity of ambient PM2.5 collected in winter in Changchun to RAW264.7 cells

Objective To understand the cytotoxicity of PM2.5 collected in winter in Changchun,Jilin province to RAW264.7 cells.Methods RAW264.7 cells were exposed to the PM2.5 collected during heavy haze episodes with five-grade air quality based on air quality index (AQI) at the doses of 0,50,100,200 and 400 μg/mL respectively.The cell viability was detected by MTT assay,Ca^2+ concentration and intracellular reactive oxygen species (ROS) and lactate dehydrogenase (LDH) release were measured by microplate reader.Apoptosis was measured by flow cytometry,the tumor necrosis factor (TNF -α) and interleukin-6 (IL-6) were detected by ELISA.Results PM2.5 at 100 μg/ml,200 μg/ml and 400 μg/ml resulted in the increase of ROS,Ca^2+,and decrease of cell viability in RAW264.7 cells with a dose-dependent manner (P<0.05).Furthermore,compared with the control group,the content of TNF-α and IL-6 increased markedly and the cell apoptosis rate increased significantly (P <0.05) with the increases of PM2.5 exposure levels.Conclusion These observations suggest that haze PM2.5 can cause inflammatory damage and oxidative stress in RAW264.7 cells,which in turn causes RAW264.7 apoptosis,likely being one of its toxicological mechanisms.