The Study On The Effects Of Nickel In Ambient PM_2.5 To The Circulate Vascular Endothelial Cells

Objective:1. To compare the concentration of the main pollutant,PM2.5 and Ni and V in PM2.5 in the nickel-contaminated area and control area; 2.To probe the effect of the nickel in ambient PM2.5 on the vascular endothelial cells' number and function in vitro and vivo and explore its possible mechanism.Methods:1.In the nickel-contaminated area and control area PM2.5 were collected from December 2009 and June to July of 2010 and then the concentration of PM2.5 as well as Ni and V were tested; 2.The ambient PM2.5 of nickel-contaminated area and control area were made into suspensions for different concentrations (0μg/ml,25μg/ml,50μg/ml,100μg/ml). After being exposed, the survival rate of ECV-304 cells was determined by MTT assay. Then Transwell Migration cabinet was applied to scan its mobility and the activity, and the LDH activity in cells' supernatant was also tested; 3.Twenty research objects were selected from the nickel-contaminated area and control area. Using the Flow cytometric analysis, CD34+/KDR+, CD34+/KDR+/CD133+ and CD34+/KDR+/CD45- three cell groups in the blood samples from the 20 objects were tested, then the number of the endothelial precursor cells was accounted, and its mobility and the activity were determined by Transwell Migration cabinet, besides that the numbers of the colony forming unit(CFU) was also tested.Results:1. Ambient monitoring results①There were not significant difference about the concentration of PM10, PM2.5, SO2 and NO2 between nickel-contaminated and control area (P>0.05):①The concentration of Ni in PM2.5 was 69 times' higher in nickel-contaminated area than in the control area(P<0.001), the concentration of V in nickel-contaminated area was almost the same as in the control area (P>0.05).2.The results of cytotoxicological study of nickel (Ni) in ambient PM2.5①With the increasing dose of exposure, ECV-304 cells' survival rate decreased gradually both in nickel-contaminated area and the control area(P<0.05), under the same exposure time and exposure dose, there were significant difference between the ECV-304 cells, survival rate coming from these two areas.②As the exposure dose increased, ECV-304 cells' LDH activity in cell supernatant fluid increased gradually(P<0.05). At the same exposure time and exposure doses, LDH activity of ECV-304 also showed significant difference in cell supernatant fluid (P<0.01).③With the increasing of exposure doses, ECV-304 cells migration number and its rate decreased gradually both in nickel-contaminated area and the control area (P<0.05); at the same exposure time and exposure dose, ECV-304 cells' migration number and its rate in nickel-contaminated area was lower than in the control area (P<0.01).3.The results of epidemiological studies①The concentration of EPCs of subjects from nickel-contaminated area were lower than from the control area(P<0.05), the number of the migration of endothelial precursor cells from nickel-contaminated area was lower than in the control area (P<0.01), the cell formed unit of the endothelial precursor cells in nickel-contaminated area was also lower than in the control area(P<0.05).Conclusion:1.During the monitoring period nickel-contaminated area shows similar concentration of PM2.5 with control area. The concentration of Ni of PM2.5 in nickel-contaminated area was 69 times as in the control area.2. After being exposed to PM2.5(Ni), the endothelial cells' survival rate reduced, and their function is changed in nickel-contaminated area.3. The number and function of endothelial progenitor cell from people who live in the nickel-contaminated area were decreased, which suggested that nickel in PM2.5 may injure endothelial progenitor cells and played an important role in cardiovascular disease.