北京大气PM2.5对A549细胞炎性因子及DNA损伤的毒性

摘要

In order to investigate the toxicity effect of atmospheric PM2.5 and its different fractions to human pulmonary epithelial cells A549 with respect to the relationship between PM2.5 dosage and cell response, the water-soluble, fat-soluble, pure particle fractions of PM2.5 (designated WSP2.5, FSP2.5 and PPP2.5, respectively) prepared from original PM2.5 samples (designated OP2.5) and OP2.5 were to treat A549 cells at different PM concentrations (10, 50, 100, 200, 400μg/mL, respectively). The MTS method was used to test the cell viability at 6h, 10h, 24h, 48h and 72h post-treatment, while ELISA and RT-QPCR were employed to detect the production of inflammatory cytokines IL-6 and TNF-α and the AP-sites counting was conducted to determine the level of intracellular DNA damage at 24h post-treatment. WSP2.5 had very limited effect to inhibit cell growth and induce inflammatory damages and DNA base deletion. FSP2.5, PPP2.5 and OP2.5 at high concentrations showed the inhibitory effect to cell growth across treatment; when cells were treated with low concentrations of FSP2.5, PPP2.5 or OP2.5, the inhibition of cell growth occurred within a short period and then disappeared over time. FSP2.5, PPP2.5 andOP2.5 treatment significantly induced the production of IL-6at both mRNA and protein levels, while WSP2.5, PPP2.5 andOP2.5 treatment significantly induced the mRNA expression of TNF-α. FSP2.5, PPP2.5 and OP2.5 treatment also induced the considerable DNA base deletion. In a word, not only the complex components adsorbed on the solid core granules of PM2.5, but also the solid core granules themselves contributed to the cytotoxicity effects.%为探讨大气PM2.5及其不同组分对人肺上皮细胞A549的毒性作用及其剂量-反应关系,将前期采集的PM2.5颗粒物用不同方法进一步制备PM2.5水溶性组分、PM2.5脂溶性组分和PM2.5单纯颗粒物,将制备的PM2.5颗粒物及其组分以不同浓度(10,50,100,200,400μg/mL)对A549细胞染毒,用MTS法分别在染毒6,10,24,48,72h后测定细胞活力,染毒24h后用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:除PM2.5水溶性组分外,其余染毒样本高浓度染毒时始终对细胞生长表现出抑制作用,其中低浓度染毒时可在较短时间对细胞生长表现出抑制作用,染毒时间较长时抑制作用减弱或消失,PM2.5水溶性组分对细胞生长抑制作用并不显著;除PM2.5水溶性组分外,其余染毒样本都显著升高了IL-6mRNA的相对表达量和IL-6蛋白的分泌,除PM2.5脂溶性组分外,其余染毒样本都显著升高了TNF-αmRNA的相对表达量;除PM2.5水溶性组分外,其余染毒样本都显著提高了DNA碱基缺失程度.总的来说,PM2.5水溶性组分在抑制细胞活力、造成炎性损伤及DNA损伤方面作用相对较小,而PM2.5所产生的毒性作用并不仅限于其所吸附的复杂成分,其中作为载体的固体核心颗粒对机体可能造成的毒性作用也不容忽视.