澳门冬季大气PM10基于DNA损伤的毒理学研究

运用质粒DNA评价法对澳门半岛的中山公园、高士德马路、氹仔岛的澳门大学3个采样点冬季PM10的氧化性损伤能力进行了研究.结果表明,3个采样点PM10的TD30值(引起30%超螺旋DNA损伤所需要的颗粒物的剂量)为中山公园采样点相对较低,其次是高士德马路采样点,澳门大学采样点最高,说明澳门半岛PM10的氧化性损伤能力大于氹仔岛.利用场发射扫描电镜及图像分析系统对颗粒物的微观形貌类型及粒度分布进行研究,并探讨了这些微观特征与颗粒物氧化性损伤能力之间的关系.结果表明,二次粒子和未知超细颗粒物的含量越高,TD30值越小,说明二次粒子和未知超细颗粒对大气颗粒物的氧化性损伤具有重要的作用.对比水溶样和全样的DNA评价结果得出,相同剂量下水溶样和全样对DNA的损伤量相似,说明大气颗粒物中的水溶组分是其氧化性损伤能力的主要来源.

A toxicological study based on DNA damage of inhalable particulates collected in Macao during winter

Plasmid DNA assay was applied to study oxidative capacity of the winter PM10 in Macao. The PM10 samples were collected at three sites, including the Sun Yat Sen Municipal Park site (SYSP) and the Av. de Horta e Costa site (AHC) in the Macao Peninsula as well as the Macao University site in the Taipa Island (TI). The TD30 values (the dosage of PM10 that caused 30% DNA damage) of the PM10 were relatively lower at the SYSP site, followed by the AHC site, with the TI site to be the highest, demonstrating that the PM10 in the Macao Peninsula had a higher toxicity than that of the Taipa Island. Field emission scanning electron microscopy (FESEM) and image analysis were used to analyse the morphology and size distribution of individual particles in PM10, and these microscopic characteristics were further combined with the oxidative capacity of PM10. A higher proportion of secondary particles and unknown ultrafine particles were associated with the lower TD30 values of PM10. The secondary particles and unknown ultrafine particles might be the important components responsible for the observed plasmid DNA damage. The water-soluble fractions and intact whole particle solutions of Macao airborne particles produce a similar plasmid assay, demonstrating that the oxidative damage by the particles in Macao was mainly sourced from the water-soluble fraction.