“Utility of a C6-glioma system for exploratory risk assessment of environmentally relevant mixtures of insecticides”

ROMERO, DM; ALAIMO A.; GOROJOD R.; KOTLER M.L.; WOLANSKY MJ

Salt Lake City, Utah. USA.

Congreso; 49th Annual Meeting and ToxExpo; 2010

SOT (Society of Toxicology)

Utility of C6-glioma cells for exploratory risk assessment of complex mixtures of organophosphate and pyrethroid insecticides Romero, DM; Alaimo, A; Gorojod, R; Kotler, ML; Wolansky, MJ Real environments and food products may carry low levels of multiple hazardous compounds. According to recent toxicological information from rats and environmental data, organophosphate (OP) and pyrethroid (PYR) insecticide residues pollute indoor and outdoor settings, each single compound in very low levels that may be considered safe for humans. Yet, there is a data gap on the neurotoxicology of complex insecticide mixtures. Here we present initial data of an exploratory, in vitro, pesticide toxicity model aimed to identify toxicologically relevant combinations of insecticides that require cumulative risk analysis efforts in in vivo models of greater human relevance. As a first task, we used rat C6-glioma cells to determine sub-effective dose-ranges for cell viability. Cell cultures were examined after insecticide exposures for 4, 12, 24 and 48 hr by optical and fluorescence microscopy. In addition, the MTT assay was carried out as a test for mitochondrial stress and general cell damage. Data from MTT assays were modeled applying Benchmark Dose Software (BMDS) analysis. Using the MTT test, we generated time- and dose (0.1 up to 50-250 uM)-effect data for two OP and two PYR compounds. In general, sub-uM exposures produced no clear evidence of citotoxicity. Higher concentrations produced dose-related drops in cell viability at 24-48 hr, save the OP acephate. The BMD15s were 6.7 uM for Chlorpyrifos, 4.4 uM for Bifenthrin, and 44 uM for Tefluthrin. Moreover, a dose-related increase in cell death-related morphological events was evident using Hoechst 33258 histological evaluations from the low uM range up. We are presently evaluating other compounds and carrying out AchE assays using the cell-viability safe dose-range determined as mentioned. in vitro, pesticide toxicity model aimed to identify toxicologically relevant combinations of insecticides that require cumulative risk analysis efforts in in vivo models of greater human relevance. As a first task, we used rat C6-glioma cells to determine sub-effective dose-ranges for cell viability. Cell cultures were examined after insecticide exposures for 4, 12, 24 and 48 hr by optical and fluorescence microscopy. In addition, the MTT assay was carried out as a test for mitochondrial stress and general cell damage. Data from MTT assays were modeled applying Benchmark Dose Software (BMDS) analysis. Using the MTT test, we generated time- and dose (0.1 up to 50-250 uM)-effect data for two OP and two PYR compounds. In general, sub-uM exposures produced no clear evidence of citotoxicity. Higher concentrations produced dose-related drops in cell viability at 24-48 hr, save the OP acephate. The BMD15s were 6.7 uM for Chlorpyrifos, 4.4 uM for Bifenthrin, and 44 uM for Tefluthrin. Moreover, a dose-related increase in cell death-related morphological events was evident using Hoechst 33258 histological evaluations from the low uM range up. We are presently evaluating other compounds and carrying out AchE assays using the cell-viability safe dose-range determined as mentioned.