A novel in vitro exposure technique for toxicity testing of selected volatile organic compounds

Abstract

Exposure to vapours of volatile chemicals is a major occupational and environmental health concern. Toxicity testing of volatile organic compounds (VOCs) has always faced significant technological problems due to their high volatility and/or low solubility. The aim of this study was to develop a practical and reproducible in vitro exposure technique for toxicity testing of VOCs. Standard test atmospheres of xylene and toluene were generated in glass chambers using a static method. Human cells including: A549-lung derived cell lines, HepG2-liver derived cell lines and skin fibroblasts, were grown in porous membranes and exposed to various airborne concentrations of selected VOCs directly at the air/liquid interface for 1 h at 37 °C. Cytotoxicity of test chemicals was investigated using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) and NRU (neutral red uptake) assays following 24 h incubation. Airborne IC 50 (50% inhibitory concentration) values were determined using dose response curves for xylene (IC 50 = 5350 ± 328 ppm, NRU; IC 50 = 5750 ± 433 ppm, MTS in skin fibroblast) and toluene (IC 50 = 10500 ± 527 ppm, NRU; IC 50 = 11200 ± 1044 ppm, MTS in skin fibroblast). Our findings suggest that static direct exposure at the air/liquid interface is a practical and reproducible technique for toxicity testing of VOCs. Further, this technique can be used for inhalational and dermal toxicity studies of volatile chemicals in vitro as the exposure pattern in vivo is closely simulated by this method. Exposure to vapours of volatile chemicals is a major occupational and environmental health concern. Toxicity testing of volatile organic compounds (VOCs) has always faced significant technological problems due to their high volatility and/or low solubility. The aim of this study was to develop a practical and reproducible in vitro exposure technique for toxicity testing of VOCs. Standard test atmospheres of xylene and toluene were generated in glass chambers using a static method. Human cells including: A549-lung derived cell lines, HepG2-liver derived cell lines and skin fibroblasts, were grown in porous membranes and exposed to various airborne concentrations of selected VOCs directly at the air/liquid interface for 1 h at 37 1C. Cytotoxicity of test chemicals was investigated using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) and NRU (neutral red uptake) assays following 24 h incubation. Airborne IC 50 (50% inhibitory concentration) values were determined using dose response curves for xylene (IC 50 = 5350 AE 328 ppm, NRU; IC 50 = 5750 AE 433 ppm, MTS in skin fibroblast) and toluene (IC 50 = 10 500 AE 527 ppm, NRU; IC 50 = 11 200 AE 1044 ppm, MTS in skin fibroblast). Our findings suggest that static direct exposure at the air/liquid interface is a practical and reproducible technique for toxicity testing of VOCs. Further, this technique can be used for inhalational and dermal toxicity studies of volatile chemica...

Combining three in vitro assays for detecting early signs of UVB cytotoxicity in cultured human skin fibroblasts

“…This paper attempts to investigate cellular damage triggered by a range of UVB radiation in vitro using human skin fibroblasts as the target cells. The assessment of cellular damage was achieved by 3 colorimetric assays selected for their reliability and reproducibility [9,10].…”

“…The seeding density of cells to the 24 well plates was previously determined and cells were seeded at a density of 500,000 cells/ml based on the linearity range studies (cell concentration versus absorbance) previously conducted [9].…”

“…Furthermore, the techniques used are rapid and reproducible as they generated toxicity profiles within hours of running the assays (Bakand et al [9]). …”

“…The in vitro assays selected are modified cytotoxicity tests (MTS, NR and LDH) developed by our lab and used extensively in measuring different biological end points ( [9]; Lestari et al [10]). …”

Toxicity of volatile organic compounds (VOCs) mixtures using human derived cells

“…Standard test atmospheres were generated using a static methodology as outlined in Bakand et al [7]. Briefly, a known quantity of volatile liquid was introduced into the glass bottle onto a filter paper.…”