Sex-Specific Variations in Acetylcholinesterase Activity Following Exposure to Pesticide-Treated Grains in Wistar Rats

Abstract

This study investigated the neurotoxic effects of chemical (specifically dichlorvos) and biological (bacteria - Pseudomonas aeruginosa and fungi - Beauveria bassiana) pesticides on acetylcholinesterase (AChE) activity in male and female Wistar rats fed with pesticide-treated rice and cowpea. AChE activity served as a biomarker of neurotoxicity. Seventy adult rats (35 males and 35 females) were randomly assigned to 14 treatment groups of five animals each and fed with 100 g of pesticide-treated or untreated grains for 10 days. On the eleventh day, the animals were sacrificed and the blood obtained through ocular puncture into a heparinized bottle. AChE activity was measured spectrophotometrically and analyzed using one-way ANOVA with significance at p<0.05. In male rats, chemical pesticide (rice) treatment significantly reduced AChE activity by 47.74% compared to control, indicating marked neurotoxicity. Conversely, chemical pesticide (cowpea) caused a 26.91% increase, suggesting compensatory enzymatic upregulation. Bacterial and fungal pesticide treatments caused substantial AChE elevation, particularly bacterial pesticide (cowpea) with a 125.4% increase over control, suggesting low neurotoxicity or enzymatic induction. In female rats, AChE activity in the chemical pesticide (rice) group showed a 9.6% increase relative to control, while cowpea (chemical) reduced activity by 17.4%. Bacterial pesticide (rice) treatment markedly decreased AChE activity by 41.5%, suggesting potential neurotoxicity in females. Fungal pesticide treatments exhibited variable effects, with AChE activity increasing by 15.7% in the rice group and decreasing by 36.4% in the cowpea group. These findings reveal sex-specific and treatment-specific neurotoxic responses, with chemical pesticides showing stronger inhibitory effects in males. Bio-pesticides, while generally safer, displayed dose- and grain-type-dependent variability. The study underscores the need for sex-inclusive neurotoxicity assessments and supports cautious use of biopesticides in food systems.