Subchronic Toxicity of a Terbufos-based Pesticide (Counter 15FC) in Adult Male Rats

This study aimed at evaluating the subchronic adverse effects of Counter 15FC (a terbufos -based pesticide formulation) in adult male Wistar albino rats, focusing on neurological, liver, kidney and reproductive functions. Five groups of animals were administered either vehicle (Control) or Counter 15FC at doses 0.1 - 3 mg/kg body weight (bwt) for 9 weeks. All surviving animals were sacrificed at the end of the treatment period, and their liver, kidneys and reproductive organs weighed. Testosterone levels, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities, biomarkers for liver function (alanine transaminase and aspartate transaminase activities), kidney function (creatinine and uric acid) and total antioxidant capacity were assessed in serum. Oxidative stress markers (thiobarbituric acid reactive species, reduced glutathione levels and catalase activity) were determined in testicular and liver homogenates. Counter 15 FC at the dose of 3 mg/kg bwt induced tremors, seizures and death of 4 animals after 6 days of experiment. The pesticide formulation at 1 mg/kg bwt inhibited AChE and BuChE after 9 weeks. Moreover, the pesticide doses 0.1 and 0.3 mg/kg bwt inhibited testicular catalase activity, while other parameters investigated remained unchanged. Overall, results from this study suggest that exposure to Counter 15 FC can be fatal. The pesticide toxicity occurs at least in part through inhibition of cholinesterase and catalase activities in nervous system and testis, respectively.