Molinelli Alejandro R, Santacana Guido E, Madden Michael C, Jiménez Braulio D
Department of Biochemistry, University of Puerto Rico, Medical Sciences Campus, Río Piedras, PR, USA.
Environ Res. 2006 Nov;102(3):314-25. doi: 10.1016/j.envres.2006.04.010. Epub 2006 Jul 13.
The importance of airborne particulate matter (PM) in causing increases in morbidity and mortality in humans has been confirmed by numerous epidemiological and laboratory studies. It has been proposed that PM might deliver transition metals to the airways were they react and generate reactive oxygen species (ROS), thus promoting the expression of inflammatory mediators, and cytotoxicity. In Puerto Rico (PR), the northern Guaynabo area is a US EPA non-attainment zone for PM10 (PM with a mass median aerodynamic diameter 10 microm), and a previous study found that organic PM10 extracts from this area were cytotoxic. The purpose of this research project is to compare the toxicity between organic PM extracts from Guaynabo (a coastal urban site) and Fajardo (a coastal rural town) based on their polarity, collection season, and geographical location. We will also evaluate if the metal content of such extracts is associated with their biological activity. PM10 filters from both locations were subjected to a sequential Soxhlet extraction using hexane and acetone. Normal and transformed bronchial epithelial cells were then exposed to the extracts. Using the neutral red assay to measure cell viability we found that coastal urban PM from PR generally exhibits higher cytotoxicity than coastal rural PM. However, this effect is dependent on the polarity of the extracts and the collection season (in winter hexane PM10 is more toxic, whereas during the summer acetone PM10 is more toxic). We also found that non-polar organic constituents in PM from PR are generally more toxic than the polar organic constituents. The main conclusion from this work is that the metal contents of the organic PM extracts from PR could play a minor role in the cytotoxicity observed. This is supported by the findings of elements such as As, V, Ni, and Cu in the most cytotoxic extracts. However, organic compounds probably play the major role. The presence of bioactive fractions of PM underscores the importance of conducting more detailed studies.
众多流行病学和实验室研究已证实，空气中的颗粒物（PM）对人类发病率和死亡率上升具有重要影响。有人提出，PM可能会将过渡金属输送到气道，在那里发生反应并产生活性氧（ROS），从而促进炎症介质的表达和细胞毒性。在波多黎各（PR），北部瓜伊纳沃地区是美国环境保护局（EPA）认定的PM10（质量中位空气动力学直径为10微米的颗粒物）未达标区域，此前一项研究发现，该地区有机PM10提取物具有细胞毒性。本研究项目的目的是根据瓜伊纳沃（一个沿海城市地区）和法哈多（一个沿海乡村小镇）有机PM提取物的极性、采集季节和地理位置，比较它们的毒性。我们还将评估这些提取物的金属含量是否与其生物活性相关。来自这两个地点的PM10过滤器先用己烷和丙酮进行连续索氏提取。然后将正常和转化的支气管上皮细胞暴露于提取物中。使用中性红试验测量细胞活力，我们发现来自PR的沿海城市PM通常比沿海乡村PM表现出更高的细胞毒性。然而，这种影响取决于提取物的极性和采集季节（冬季己烷PM10毒性更强，而夏季丙酮PM10毒性更强）。我们还发现，PR地区PM中的非极性有机成分通常比极性有机成分毒性更大。这项工作的主要结论是，PR地区有机PM提取物中的金属含量在观察到的细胞毒性中可能起次要作用。这一结论得到了细胞毒性最强的提取物中砷、钒、镍和铜等元素的研究结果的支持。然而，有机化合物可能起主要作用。PM生物活性部分的存在凸显了进行更详细研究的重要性。
