| Airborne fine particles can penetrate to the regions of lung and the alveoli and have heavily damage effect on health. The study about airborne particles has been paid more and more attention at home and abroad. In this study, we investigated the DNA damage and oxidative stress effects of dust storms fine particles.The meaning of airborne fine particles (PM2.5) is particles with aerodynamic diameter less than 2.5 μm. The PM2.5 samples in the study were collected by using PM2.5 high volume air sampler (Thermon Anderson, USA) in Wuiwei city, Gansu province and Baotou city, Inner Mongolia Autonomous Region from March 1 to May 31, 2004.This study is comprised of two parts, the toxicology effects of dust storm PM2.5 were investigated by in vitro and in vivo study, respectively. In vitro study, rat alveolar macrophages were exposed to PM2.5 samples, their water-soluble fractions and solvent-extractable organics from dust storm and normal weather, respectively. DNA damage of rat alveolar macrophages was detected with single cell gel electrophoresis technique (SCGE) and cytotoxicity was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenylte-trazolium bromide (MTT) reduction assay. The results show: (1) PM2.5 samples, their water-soluble fractions and solvent-extractable organics from dust storm and normal weather caused cytotoxicity to alveolar macrophages and the cell viability was decreased in a dose-response manner. (2) PM2.5 samples, their water-soluble fractions and solvent-extractable organics of both normal PM2.5 and dust storm PM2.5 could lead to DNA damage in a dose-dependent manner;the samples of normal PM2.5 made higher DNA damage than those of dust storm PM2.5. (3) The solvent-extractable organicsmade higher DNA damage than the water-soluble fractions of both normal PM25 and dust storm PM2.5. It was suggested that the organic compounds are the main contributor to DNA damage. (4) No significant difference were observed in DNA damage of dust storm PM2.5 and their water-soluble fractions and solvent-extractable organics between Baotou city and Wuwei city, suggesting that the genotoxicity compounds are similar in dust storm PM2.5 of these two districts.In vivo study, after rats were intratracheally instilled 24 h, the activities of SOD, the contents of GSH and the levels of LPO in hearts, livers, lungs of rats were measured. DNA damage of lung cells of rats was detected with SCGE. The results show: (1) Dust storm PM2.5 and normal weather PM2.5 instillation caused significantly decrease of SOD activities at higher concentration in livers and lungs. The contents of GSH in lungs appeared a dose-dependent decrease comparing with control group, whereas PM2.5 instillation at low concentration caused a significant increase and at higher PM2.5 instillation caused a significant decrease in livers of rats. The levels of LPO in lungs, hearts and livers all appeared significantly dose-dependent increase, but the changes of GSH contents and SOD activities in hearts of rats were statistically insignificant. (2) Both dust storm PM2.5 and normal weather PM2.5 could lead to DNA damage of lung cells in a dose-dependent manner. (3) The effects made by the same concentration samples respectively from Wuwei normal weather, Wuwei dust storm weather, Baotou normal weather and Baotou dust storm weather have no significant difference on the same examined index.It concluded that: Both dust storm PM2.5 and normal weather PM2.5 could lead to DNA damage in alveolar macrophages and lung cells and oxidative stress in lungs, hearts and livers of rats. During dust storm periods, ambient PM2.5 mass concentration was significantly (P<0.05) higher thanthat in normal weather, so the toxicology of dust storm PM2.s should be higher than that of normal weather PM2.5. |
PDF Full Text Request