Single dose neurotoxicity screening studies of insecticide combination (Cypermethrin and Profenofos) in Wistar rats

The present investigation has been taken up to determine the toxic effects of combination insecticide (Profenofos 40% + Cypermethrin 4% EC) on nervous system of rats. A single oral dose of test substance was administered to five rats per sex at a concentration of 25, 75 and 225mg/kg body weight to experimental animals. The animals were observed under carefully standardized conditions with sufficient frequency to ensure the detection and quantification of behavioral and/ or neurologic abnormalities. In addition, serum cholinesterase was estimated after 24 hours of dosing. Motor activity of individual animal was measured using an automated device. Perfused (in-situ) nervous tissues were examined microscopically. The test article at the dose level of 75 and 225 mg/kg induced treatment related and dose dependent neurobehavioural alterations in rats of either sex. However, observed alterations were reversible, further no structural/ histopathological alterations were apparent. Single dose of test article at 25 mg/kg did not reveal any toxic signs or neurobehavioral alterations hence, it is considered to be the No Observed Adverse Effect Level (NOAEL).