Abstract:To explore the inducing effect of traffic related PM2.5 on apoptosis of human peripheral blood lymphocytes and its possible mechanism, so as to provide experimental basis of immunotoxicity of traffic related PM2.5. Human peripheral blood lymphocytes were exposed to 0, 50, 100, 200 g/ml PM2.5 for 24 h and 48 h and FITC-AnnexinV/PI staining and flow cytometry was used to detect the early apoptosis and necrosis of lymphocytes. The expression of Caspase-3 and CREB protein in human peripheral blood lymphocytes and the intracellular cAMP content was measured by Western blot and ELISA after exposure to PM2.5 at 0, 20, 80 and 320 g/ml for 24 h , 48 h and 72 h. The results show that after cells were exposed to 50, 100 and 200 g/ml PM2.5 for 24 h and 48 h, the early apoptosis and necrosis of lymphocytes were higher than those in the normal saline group, with statistically significant differences (P<0.01), and there was a dose-effect relationship. The protein expression level of Caspase-3 in each dose group was higher than that in the control group after 24 h, 48 h and 72 h of 20, 80, 320 μg/ml PM2.5 exposure, and except for 80g/ml PM2.5 exposure for 72 h, the differences were statistically significant (P<0.01). After 24 h, 48 h and 72 h of 320 g/ml PM2.5 exposure, the intracellular cAMP content was increased compared with the normal saline group (P<0.05). And the expression level of CREB decreased with the increase of PM2.5 concentration after exposure for 72 h (P<0.01). It is concluded that traffic related PM2.5 can induce apoptosis of human peripheral blood lymphocytes, and intracellular cAMP and CREB are involved in the regulation of apoptosis.