EFECTO DEL PARATHION SOBRE EL íNDICE DE APOPTOSIS EN HEPATOCITOS DE RATONES CF1

chemical environmental pollution is a major problem at present. agropesticides are relevant in this regard, since they affect human and animal health (draper, 1985; rodríguez & bustos-obregón, 2000). parathion" (pt), an organophosphorate pesticide inhibits acetylcholinesterase and is metabolized in liver, lung and brain. it is transformed in paraoxon (po), its active metabolite (chambers & chambers, 1990 and siller et al., 1997). this work analizes the effect of a single dose of pt on the apoptotic index of cf1 mouse hepatocytes. male cf1 mice (8 to 10 weeks old, average weight of 30 g) were treated with a single injection of pt, of 20 mg/kg body weight (sobarzo & bustos-obregón, 2000). the animals were sacrificed at 1, 8, 16, 28 and 50 days after injection. histological analysis of hepatic tissue was done by light microscopy for counting of apoptotic (and binucleated) cells in he stained slides. it has been postulated that pt is carcinogenic and that it modifies the ability of hepatocytes to regenerate (metcalfe & streuli, 1997 and fausto, 2000). we conclude that pt is cytotoxic even at low concentrations, since it increases apoptosis and affects the normal homeostasis of the hepatic tissue