Abstract: Objective: To investigate the interactive effects of different temperatures and ambient PM2.5 on the rat alveolar macrophages.Methods: The rat alveolar macrophages were collected. The cells were exposed in vitro to 18℃, 24℃, 30℃, 37℃ and 43℃ with PM2.5 at the concentrations of 100 μg/ml, 50 μg/ml, 25 μg/ml and 0 μg/ml respectively. The cells were cultured in the different cases for 8 hours, then cytotoxicity was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)reduction assay and phagocytosis function of macrophages was assessed by neutral red absorption test.Results: The relative survival rate and the cytophagocytic function of alveolar macrophages of rats among the different concentration groups decreased significantly (P<0.05) compared with the blank control group. Both were dose-dependent. The 37℃ group had the highest level of relative survival rate and the cytophagocytic function compared with other different temperatures groups. Interactive effect of different temperatures and ambient PM2.5 was not observed. But the lower temperature and the higher PM2.5 concentration group had stronger toxicity to alveolar macrophages.Conclusion: The results suggested that different temperatures and ambient PM2.5 have cytotoxicity on alveolar macrophages,injuring the phagocytosis. The two factors had some interaction.

Key words: different temperatures, ambient PM2.5, cytotoxicity, cytophagocytic, macrophages