An Integrated in Vitro Approach for Toxicity Testing of Airborne Contaminants

Abstract

While it is possible to establish the chemical composition of air pollutants through conventional air sampling and analytical techniques, such data do not provide direct measures of toxicity and the potential mechanisms that induce adverse effects. The aim of this study was to optimize in vitro methods for toxicity testing of airborne contaminants. An integrated approach was designed in which appropriate exposure techniques were developed. A diversified range of in vitro assays using multiple human cell systems were implemented. Direct exposure of cells to airborne contaminants was developed by culturing cells on porous membranes in conjunction with a horizontal diffusion chamber system. Concentration-response curves were generated allowing the measurement of toxicity endpoints. Regression analysis indicated a significant correlation between in vitro and published in vivo toxicity data for the majority of selected chemical contaminants. Airborne IC₅₀ values were calculated for selected volatile organic compounds (xylene, 5350 ± 328 ppm > toluene, 10500 ± 527 ppm) and gaseous contaminants (NO₂, 11 ± 3.54 ppm > SO₂, 48 ± 2.83 ppm and > NH₃, 199 ± 1.41 ppm). Results of this study indicate the significant potential of in vitro methods as an advanced technology for toxicity assessment of airborne contaminants.

The authors thank Dr. Christian Khalil for his technical assistance and Dr. Zhanhe Wu (Westmead Hospital, Sydney) for supplying the human cells. The authors also thank Dr. Paul Thomas (Department of Medicine, Prince of Wales Clinical School) and Dr. Maria Kavallaris (Experimental Therapeutics Program Children's Cancer Institute Australia for Medical Research) for initially providing the A549 cells.