Characterization of cellular and molecular markers of toxicity in C6-Glioma cells exposed to modern pyrethroids.

ROMERO, D.M., WOLANSKY, M.J., KOTLER, M.L.

San Antonio, Texas

Congreso; Annual Meeting - Society of Toxicology; 2013

Society of Toxicology (USA)

Characterization of cellular and molecular markers of toxicity in C6-glioma cells exposed to modern pyrethroids. Pyrethroids (PYRs) are insecticides increasingly used in various pest control applications. Low levels of PYR residues have been detected in diverse environmental samples, food and human urine. In vitro systems may be useful to characterize the diversity of primary and secondary toxicogenic pathways that may account for the pyrethroid-type specific divergence in clinical syndromes observed in small rodents. We use C6-glioma cell cultures to identify toxicologically relevant PYR exposures that may require cumulative risk assessment efforts in animals in vivo. Four compounds (bifenthrin, tefluthrin, α-cypermethrin, deltamethrin) were examined after 24 h of PYR exposure. We also evaluated pyrethroid actions in C6 cells treated with sodium butyrate (NaBu) which induce an astrocyte-like phenotype. Thresold dose and EC15(24h) estimates were obtained after modeling MTT test data. In order to study subcellular integrity and signaling pathways with greater specificity and sensitivity, Mitotracker-Red and Neutral Red staining (informing on mitochondrial and lysosomal status, respectiv.), caspases and p53 (cell deah related markers), AchE (an insecticide neurotoxicity related target) and GFAP (glia-specific xenobiotic response) were then examined. Low μM exposures induced dose-related declines in cell viability in both cell systems. We further found dose-related increases in fragmented mitochondria and mitochondrial membrane potential disruption in C6 cells. Increase in cell death related proteins and drop of GFAP levels were also observed in NaBu-treated cells. In addition, cholinesterase inhibition was not evident below EC15 levels for general cell viability for any test chemical. These results confirm that μM exposures affect cell viability markers unrelated to the proposed primary mode of action of pyrethroids, and that the classically proposed target cell for pyrethroids, the neuron, is not the only cell type that may be susceptible of citotoxicity and severe cell damage in mammals.