Biochemical alterations induced by the acute exposure to combination of chlorpyrifos and lead in Wistar rats

Chlorpyrifos, a well known organophosphorus insecticide and heavy metal lead, was challenged to Wistar rats to study their interactive effects on biochemical parameters (clinical pathology) after acute exposure via oral gavaging. Hematology and clinical chemistry parameters were estimated after 14 days of exposure. In addition, serum butryl and RBC cholinesterase was estimated on days 3 and 15 of experimentation. The study was conducted using two different dose levels of chlorpyrifos and lead acetate and grouped into seven groups. The parameters of hematology and serum chemistry were analysed through automatic analyzers. No treatment related or interactive effects were noticed in hematology values except for the reduced RBC, Hb content and HCT values in lead treated animals at 1000mg/kg. A significant decrease in both serum and RBC cholinesterase enzymes were noticed in animals treated with chlorpyrifos at 50 mg/kg and in combination group (chlorpyrifos 50 + lead 1000 mg/kg), and increased inhibition along with delayed recovery was observed in the animals of combination group (i.e., chlorpyrifos plus lead). Chlorpyrifos in presence of lead increases the inhibition of both serum and RBC cholinesterase enzymes. The long lasting or persistence effects of CPF along with and lead may result in impaired cognitive functions of brain considering the role of cholinesterases in neuronal architecture of brain and other normal functioning of nervous system. Therefore, simultaneous exposure to a combination of chlorpyrifos and lead is considered to be more dangerous than to an exposure of either alone. In addition, serum chemistry revealed changes in concentrations of glucose and sodium owing to lead treatment.