RESUMO
Objective To study the effects of PM2.5 and PM10 of dust storm on the secretion of nitrogen oxide(NO), interleukin-8 (IL-8) and tumor necrosis factor-?(TNF-?)in the alveolar macrophages(AM)of rat in vitro. Methods PM2.5 and PM10 were collected during dust storm period in the urban area of Beijing. The tested cells were primary cultured alveolar macrophages. Cytotoxicity of the particles was measured by MTT assay. The content of NO was determined using Griess reagent. The levels of cytokines IL-8 and TNF-? were determined using radioimmunity assay. Results After treatment for 24 h, PM2.5 and PM10 caused cytotoxicity to AM and the survival rate of the cells was decreased with the increasing exposure dose of the dust to the rats and the survival rate of the cells in the high dosage group was 80% of the control group. At concentrations of 20～150 ?g/ml, PM2.5 and PM10 increased the secretion of NO, TNF-? and IL-8 in AM in a dose-dependent manner. The cytotoxicity of PM2.5 was stronger than that of the PM10 at the same concentration, while the effects on the increasing secretion of NO, IL-8 and TNF-? induced by PM2.5 was smaller than that of the PM10. Conclusion PM2.5 and PM10 of dust storm could induce the secretion of inflammatory factors NO, IL-8 and TNF-? in rat AM.