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

ROMERO, D.M; ALAIMO, A; GOROJOD, R; KOTLER, M.L; WOLANSKY, M.J.

Congreso; Primera Reunión Conjunta de Neurociencias; 2009

Taller Argentino de Neurociencias y a la Sociedad Argentina de Investigación en Neurociencias (SAN, ex- Sociedad Argentina de Neuroquímica).

Real environments and food products may carry low levels of multiple hazardous compounds having diverse modes of action. For instance, according to recent single-compound toxicological information from rats and environmental data, organophosphate (OP) and pyrethroid (PYR) insecticide residues pollute indoor and outdoor settings but in levels that imply no health risk for humans. Here we present an exploratory, in vitro model, aimed to identify environmentally relevant insecticides exposure situations that require CRA-like research efforts in in vivo models of greater human relevance. We will show time (4-24-48 h)- and dose (0.1-250 uM; DMSO-vehicle control)-effect data for two OP and four PYR compounds. We use a C6-glioma culture system and a battery of effect measures to examine the individual action of these insecticides. Moreover, two fetal bovine serum (FBS) conditions are assayed (FBS 2-10%). Using 24h-exposed, C6 cultures in D-MEM supplemented with 2% FBS, followed by MTT assays for citotoxicity in 96-well plates, a high correlation between BMD15 estimates for cell viability and rat oral LD50s was apparent for three PYRs deltamethrin>bifenthrin>tefluthrin). The BMDS for chlorpyrifos (OP) showed a divergence from this relative potencies trend. Acephate (OP) produced no evident C6-cell viability decrease in any exposure condition. We are presently testing if Hoechst-33258 cytological observations and AchE assays in the C6 system may help interpreting above findings. These pilot studies will be used to appropriately design in vivo, environmentally relevant OP-PYR mixture studies aimed to test additivity using a battery of biochemical and neurobehavioral endpoints of neurotoxicity in the rat.