Background: Organophosphorus pesticides exert their toxic effects mainly by the inhibition of acetylcholinesterase (AChE), which is related to emotional disorders, such as depression. Atropine-oximes therapy is commonly used; however, the efficacy of oximes in the reactivation of AChE has been inconsistent. The objective of this study was to investigate the possible neuroprotective effect of (3Z)-5-Chloro-3-(hydroxyimino)indolin-2-one (Cℓ-HIN), a compound that combines the isatin and oxime functional groups, in rats exposed to malathion. The effect of Cℓ-HIN on the AChE activity and the BDNF-Trkβ pathway in the prefrontal cortex of malathion-exposed rats were tested.
Methods: Wistar male rats were co-treated with Cℓ-HIN [50 mg/kg (p.o.) (3 mL/kg)] and/or malathion [250 mg/kg (i.p.) (5 mL/kg)] and performed behavioral tests twelve hours after these exposures.
Results: The Cℓ-HIN reversed the increased immobility time in the forced swimming test and the decreased grooming time in the splash test induced by malathion, but any significant difference was observed in locomotion analysis. These results demonstrate the antidepressant-like effect of Cℓ-HIN. The cortical AChE activity was reactivated by Cℓ-HIN in rats exposed to malathion. Malathion induced an increase in Trkβ and a decrease in BDNF levels in the prefrontal cortex of rats, which were avoided by Cℓ-HIN.
Conclusion: These findings support the hypothesis that Cℓ-HIN is an AChE reactivator with antidepressant-like properties, which is related to the improvement of BDNF-Trkβ signaling after acute exposure to malathion in rats. Thus, the results allow suggesting the potential use of Cℓ-HIN as an oxime-based therapy against the neurotoxic effects of malathion.
Keywords: Acetylcholinesterase; Isatin; Neurotrophic factor; Organophosphate; Oxime.
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