The Study Of Traffic-related PM2.5on Calcium Homeostasis And Its Regulatory Mechanism In Jurkat T Cell

Objective: In order to study the effect of traffic-related PM2.5on3phosphoric acid inositolreceptor and ryanodine recetor channel in jurkat T cell, which may affect calcium homeostasis，and the contribution of Ca²⁺-Mg²⁺ATPase to calcium homeostasis and the regulation of calciumsignal by calmodulin. This will provide the theoretical and experimental supports for the vehicleexhaust immune toxicity.Methods: The toxicity of cellular proliferation caused by traffic-related PM2.5was determinedby MTT. The intracellular calcium concentrations([Ca²⁺]i)in different concentrations ofPM2.5groups, heparin group, heparin and PM2.5group, procaine group, procaine and PM2.5group were detected by fluorescence spectrophotometry. The activity of Ca²⁺-Mg²⁺ATPase wasdetermined by special kit. The expressions of CAM mRNA and protein were measured byQRT-PCR and Western Blot.Results:1. The effect of PM2.5on proliferation of Jurkat T cell: compared to saline control group, therewas no statistical difference in SI from the5g/mL to80g/mL PM2.5group, the SI of Jurkat Tcell decreased markedly in the320g/ml and800g/ml groups.2. While resting and active Jurkat T cells were stimulated by different concentrations of PM2.5for three hours, the [Ca²⁺]i level in100g/ml of PM2.5exposure group was the highest, the[Ca²⁺]i levels in200g/mL of PM2.5group decreased. There was no signicant difference for[Ca²⁺]i levels among different groups of the resting cells, but there was significant difference for[Ca²⁺]i levels among all groups of the active cells（p<0.05）. After resting and active Jurkat Tcells were stimulated for1h,3h,6h,12h with different concentrations of PM2.5, the [Ca²⁺]ilevels in100g/ml of PM2.5was the highest, the [Ca²⁺]i levels gradually reduced with the timeincreasing, there were significant difference among these groups（p<0.05）. Morever, the [Ca²⁺]ilevels in different time of PM2.5groups were significantly different from their own controlgroups（p<0.05）.3. When the resting cells were incubated with different concentrations of heparin and100g/mlPM2.5for three hours,100g/ml and120g/ml of heparin can inhibit the increased [Ca²⁺]i levelsstimulated by100g/ml of PM2.5, and there were significant difference compared with the alonePM2.5group, p<0.01. For active Jurkat T cells, each concentration of heparin decreased theincreased [Ca²⁺]i levels caused by PM2.5, which had significant difference compared with the control, p <0.01. Different concentrations of procaine and100g/ml of PM2.5stimulated theresting and active cells for three hours, various concentrations of procaine significantlydecreased the [Ca²⁺i level, compared with the control, p <0.05or p <0.01..4. Resting and active Jurkat T cells were stimulated by different concentrations of PM2.5forthree hours, the mRNA expression of CAM in100g/ml of PM2.5group was the lowest, therewas significant difference compared to the saline group（p <0.05）. And the protein expressionof CAM gradually decreased with the elevated PM2.5concentrations, it showed an obviousdose-response relationship（p <0.05）.Conclusions: Traffic-related PM2.5can induce the disorder of intracellular calcium homeostasisin Jurkat T cell. The intracellular IP3receptor and ryanodine receptor channel are involved incalcium influx. Traffic-related PM2.5can inhibit transmission calcium sigaling of CAM.