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目的:研究大气细颗粒物(PM 2.5)对体外培养的肺泡Ⅱ型上皮细胞系MLE-12细胞活性、炎性因子分泌及其水通道蛋白5mRNA表达的影响,探讨PM 2.5对呼吸系统的损伤及其机制。方法:采集大气中的PM2.5,并制成悬浮液,MLE-12细胞暴露于不同浓度的PM2.5处,用MTT比色法测定细胞存活力,放射免疫法测定炎性因子TNF-α、IL-6和IL-8的含量,荧光实时定量PCR法检测AQP5 mRNA的表达。结果:MTT实验中不同浓度的PM2.5作用于MLE-12细胞24 h、48 h后,细胞存活率显著下降,并呈浓度效应关系。炎性因子测定中,随着PM2.5浓度的增加,PM2.5诱导MLE-12细胞产生炎性因子TNF-α、IL-6和IL-8的浓度逐渐升高(P<0.05)。在0.025~0.20 mg/m L的质量浓度范围内,随着PM2.5染毒液浓度的增加,MLE-12中AQP5mRNA表达水平逐渐降低,且与对照组相比,差异有统计学意义(P<0.05)。结论:PM2.5通过诱导MLE-12细胞的炎症反应及AQP5蛋白表达降低引起MLE-12细胞的活性降低,促进细胞凋亡。
OBJECTIVE: To study the effect of PM 2.5 on the activity of alveolar type Ⅱ epithelial cell line MLE-12, the secretion of inflammatory cytokines and the expression of aquaporin 5 mRNA in vitro, and to investigate the effects of PM 2.5 on the respiratory system and its expression mechanism. Methods: PM2.5 was collected from the air and made into a suspension. MLE-12 cells were exposed to different concentrations of PM2.5. Cell viability was measured by MTT colorimetric assay. The levels of TNF-α , IL-6 and IL-8 levels were detected by real-time quantitative PCR method to detect the expression of AQP5 mRNA. Results: After treated with different concentration of PM2.5 for 24 h in MLE-12 cells in MTT assay, the cell viability decreased significantly with a concentration-dependent effect. With the increase of PM2.5 concentration, PM2.5 induced the production of inflammatory cytokines TNF-α, IL-6 and IL-8 in MLE-12 cells gradually increased (P <0.05). Within the concentration range of 0.025-0.20 mg / m L, the expression level of AQP5 mRNA in MLE-12 gradually decreased with the increase of PM2.5 inoculum concentration, and the difference was statistically significant compared with the control group (P < 0.05). CONCLUSION: PM2.5 can reduce the activity of MLE-12 cells and induce cell apoptosis by inducing the inflammatory response of MLE-12 cells and decreasing the expression of AQP5 protein.