The Study Of Cellular Immunotoxicity And Related Mechanism Caused By Automobile Exhaust PM_2.5

The study of cellular immunotoxicity and related mechanism caused by automobile exhaust PM2.5PartⅠThe cellular immunotoxicity and apoptosis of school-age children induced by exhaust pollutionObjective:To discuss the impact of immunotoxicity and apoptosis of school-age children induced by exhaust pollution, to effectively control pollution and protect the health of the population and to provide the scientific basis.Methods:The concentration of PM2.5 was determined by mass method. The concentration of NOx was detected by Saltzman method. The concentration of CO was measured by non-dispersive infrared absorption method. The lymphocyte CD3+/CD4+/CD8+ subsets, CD4+/CD8+ and apoptosis of early and necrosis were measured by flow cytometry. DNA ladder was measured by agarose gel electrophoresis. The expression of caspase-3 protein was measured by western blot.Results:At crossroad A, daily average concentration of PM2.5 was 0.810 mg/m3, which was significantly higher than that at crossroad B (0.323 mg/m3)(P<0.05). The concentration of CO and NOx at crossroad A was 5.054 mg/m3 and 0.106 mg/m3 respectively, which was much higher than that crossroad B (0 mg/m3 and 0.063 mg/m3), P<0.01. The children peripheral blood lymphocytes percentage of CD3+, CD4+, CD4+/CD8+ in the contaminated A school were 58.595, 30.027,1.407, Those in the clean B school were 66.572,37.690,1.787. There was significant difference (P<0.05) between percentages of CD3+, CD4+,CD4+/CD8+ of the two school-age children peripheral blood lymphocytes. The difference of the CD8+ between two schools had no statistical significane. Rates of the lymphocytes early apoptosis and necrosis in the school children of A school were 4.351,0.884, while those in the B school were 2.099,1.062. By analyzing the rate of early apoptosis of school-age children in the two regions, there was a significant difference (P<0.05) and the difference of the necrosis had no statistical significane. From the linear correlation analysis of CD3+, CD4+, CD8+, CD4+/CD8+ and the rate of early apoptosis and necrosis, CD3+ and early apoptosis, necrosis were negatively correlated, the pearson coefficients were -0.293,-0.248; P values were 0.001,0.003; CD4+ and early apoptosis, necrosis were negatively correlated, pearson coefficients were -0.230,-0.224, P values were 0.006,0.008. But CD8+, CD4+/CD8+ and early apoptosis and necrosis were not relevant. The DNA ladder-positive rate of heavy contaminated area is 37.9% and the DNA ladder-positive rate of less contaminated area is 27.9%. The positive rate of heavy contaminated is slightly higher than the less contaminated, but there is no significant difference. The caspase-3/β-actin gray value of 2.008 of the heavily polluted area higher than the light-polluted area (1.342), but there is no statistically significant difference.Conclusions The inhibitition of cell immunity of exhaust pollution on school-age children may be caused by apoptosis.PartⅡThe immunotoxicity and related mechanism of exhaust PM2.5 on human peripheral blood lymphocytesObjective:To discuss the immunotoxicity and related mechanism of PM2.5 exhaust on human peripheral blood lymphocytes.Methods:The concentration of exhaust PM2.5 exposure was determined by MTT and LDH. The lymphocyte CD3+/CD4+/CD8+ subsets, CD4+/CD8+ and apoptosis of early and late were measured by flow cytometry. The [Ca+]i changes of cell was detected by fluorescence spectrophotometry. Na+-K+-ATP enzyme and Ca2+-Mg2+-ATP enzyme was determined by the relative kit.Results:The effect of PM2.5 on proliferation in lymphocyte:compared to control group, there was no statistical difference of SI in the 5μg/mL,20μg/mL,80μg/mL PM2.5 group. The SI of lymphocyte decreased markedly in both the 320μg/ml and 800μg/ml group. The level of LDH in 5μg/mL,100μg/mL PM2.5 group increased slightly than control group, but it was not statistically significant. The level of LDH in 500μg/mL,800μg/mL PM2.5 group had significantly increased than control group, and the difference was statistically significant. The T-lymphocyte subsets (CD3+, CD4+ percentage levels, CD4+/CD8+ ratio) of 50μg/mL, 100μg/mL,200μg/mL of PM2.5 exposure 24h and 48h were lower than the control group. The difference of the CD3+ percentage between the exposure groups and the control group after 48h exposure was statistically significant (P<0.05). After 24h and 48h exposure, With the exposure dose increasing, early apoptosis and necrosis were higher than the control group and the level of early apoptosis and necrosis in 100μg/mL,200μg/mL group was significantly increased compared with the control group. After 1h,3h,6h,12h,24h of PM2.5 exposure, lymphocyte [Ca2+]i levels of 200μg/mL groups were higher than the control groups, however, except 24h,the lymphocyte [Ca2+]i levels of 200μg/mL PM2.5 group were significantly different from that in control group(P<0.05). The control groups were not significantly different from different time of PM2.5 exposure(P>0.05); The [Ca2+]i levels at 3h of PM2.5 exposure was the highest, the [Ca2+]i levels gradually reduced with the extension over time,there was a statistically significant difference between the 3h and 24h. The lymphocyte [Ca2+]i level increased with the exposure concentration at 3h, the levels of lymphocyte [Ca2+]i in either the 100μg/mL or 200μg/mL group were increased than that in control group(P<0.05). As the dose of PM2.5 exposure increased, Na+-K+-ATP enzyme and Ca2+-Mg2+-ATP enzyme activity decreased and the difference of the Na+-K+-ATP enzyme activity between 200μg/mL group and control group was statistically significant(P<0.05).Conclusions:Exhaust PM2.5 can cause immune suppression of human peripheral blood lymphocytes, the possible mechanisms were the apoptosis of cell and the imbalance calcium homeostasis...