Dose-Dependent Effects of Subchronic Exposure to Glyphosate-Based Herbicide on Behavior and Biochemical Alterations in Adult Rats

Abstract

The widespread use of glyphosate-based herbicides (GBH) in agricultural practices raises major concerns regarding potential human toxicity. Mounting evidence from prior studies has delineated a direct link between GBH exposure and the development of neurodegenerative disorders. These compounds are also suspected of being involved in the induction of affective disorders. The present study was undertaken to examine the dose-dependent impact of GBH exposure over 8-week period on anxiety-and depression-like behaviors in male Wistar rats, administering daily subcutaneous injections of four different doses 25, 50, 75, and 100 mg/kg of GBH while a control group received 0.9% NaCl. Based on behavioral tests (the open field, elevated cross maze, and forced swim), behavioral alterations were detected, specifically anxiety levels and depressive behavior. Simultaneously, hippocampal oxidative stress markers (catalase, nitric oxide, and lipid peroxidation) were assessed to elucidate the involvement of oxidative stress (OS) in the observed effects. Our results delineate a clear dose-dependent effect of GBH, revealing escalated anxiety and depression-like behaviors at doses of 75 and 100 mg/kg following subchronic GBH exposure. Notably, markers of OS exhibited discernible alterations solely at 75 and 100 mg/kg, with no significant variation observed at lower doses (25 and 50 mg/kg). Our study confirms the dose-dependent effect of subchronic exposure to GBH, implicating markers of OS in the hippocampus as potential contributors to the observed neurobehavioral changes. Thus, our findings underscore OS as a plausible mechanism explaining the underpinnings of the neurotoxic effects observed following exposure to GBH.