Toxicological assessment of industrial solvents using human cell bioassays: assessment of short-term cytotoxicity and long-term genotoxicity potential

Abstract

There is an increasing demand for simple toxicological screening methods to assess the human health risk associated with exposure to environmental toxicants. Such screening tools should allow for risk evaluation in terms of both short-term/acute toxicity and longer-term genetic damage, which may lead to mutagenicity and carcinogenicity. We employed a battery of human cell bioassays using the human hepatoma cell-line, HepG2, to assess the cytotoxic and genotoxic potential of environmental pollutants. Here, we demonstrate direct application of these human cell bioassays to the toxicological assessment of a number of industrial solvents that are in common use worldwide. HepG2 cells were exposed to various solvents at concentrations ranging from 25 to 500 ppm. The cells were then analysed using specific protocols for four different adverse effects: cell death/acute cytotoxicity using a neutral red uptake assay, altered enzyme function (often an indicator of cell stress) using the ethoxyresorufin O-deethylase (EROD) bioassay, DNA single strand breaks (SSB), and DNA repair induction, which evaluates mutagenic activity. Using the positive controls, linear dose-response curves were achieved for all four bioassays. The high sensitivity of the tests allowed for environmentally meaningful assessments, and precision studies showed excellent reproducibility for all four bioassays. Comparing the results of the four bioassays on each of 16 industrial solvents allowed for ranking of the anticipated relative human toxicity of these solvents, which were comparable with data from standard toxicity tests and human occupational data. Overall, the study clearly supports the application of the HepG2 cell bioassay system for rapid toxicological screening of many candidate toxicants for both short- and long-term toxicity potential.

Camel urine inhibits the cytochrome P450 1a1 gene expression through an AhR-dependent mechanism in Hepa 1c1c7 cell line

“…To test our hypothesis, we have first assessed the potential effect of three camel urines, obtained from, lactating, pregnant and virgin camels, on the induction of Cyp1a1 by TCDD using EROD as a probe for Cyp1a1 activity in Hepa 1c1c7 cells (Hasspieler et al, 2006). Our results showed that all the three camel urines tested altered EROD activity to varying extents in a urine-dependent fashion.…”

Camel Milk Modulates the Expression of Aryl Hydrocarbon Receptor-Regulated Genes,Cyp1a1, Nqo1, andGsta1, in Murine hepatoma Hepa 1c1c7 Cells

“…Thus Cyp1a1 induction is considered a useful biomarker of exposure to carcinogenic substances [26]. Accordingly, we have first examined the potential effect of camel milk on the expression of Cyp1a1 gene after induction by TCDD using EROD as a probe for Cyp1a1 activity [27]. Our results showed that camel milk (fat-free) at all concentrations tested reduced Cyp1a1 EROD activity in a concentration-dependent manner (Figure 2).…”