(3Z)-5-Chloro-3-(Hydroxyimino)indolin-2-one attenuates hyperglycemia, increased hepatic glycogen content and hepatic damage induced by malathion acute exposure in rats

The diabetogenic effects of pesticides: Evidence based on epidemiological and toxicological studies

While the use of pesticides has improved grain productivity and controlled vector-borne diseases, the widespread use of pesticides has resulted in ubiquitous environmental residues that pose health risks to humans. A number of studies have linked pesticide exposure to diabetes and glucose dyshomeostasis. This article reviews the occurrence of pesticides in the environment and human exposure, the associations between pesticide exposures and diabetes based on epidemiological investigations, as well as the diabetogenic effects of pesticides based on the data from in vivo and in vitro studies. The potential mechanisms by which pesticides disrupt glucose homeostasis include induction of lipotoxicity, oxidative stress, inflammation, acetylcholine accumulation, and gut microbiota dysbiosis. The gaps between laboratory toxicology research and epidemiological studies lead to an urgent research need on the diabetogenic effects of herbicides and current-use insecticides, low-dose pesticide exposure research, the diabetogenic effects of pesticides in children, and assessment of toxicity and risks of combined exposure to multiple pesticides with other chemicals.

Acute and chronic effects of the organophosphate malathion on the pancreatic α and β cell viability, cell structure, and voltage-gated K+ currents

Studies indicate that the pesticide malathion may have a role in diabetes. Herein, we determined the effects of different concentrations of malathion on survival, ultrastructure, and electrophysiologic islet cell parameters. Acutely, high concentrations of malathion (0.5 or 1 mM) increased cell death in rat islet cells, while low concentrations (0.1 mM) caused signs of cell damage in pancreatic α and β cells. Exposure of RINm5F cells to malathion for 24 or 48 h confirmed the reduction in β-cell viability at lower concentrations (0.001-100 µM). Chronic exposure of mouse pancreatic α and β cells to 3 nM of malathion led to increased voltage-gated K⁺ (K_v) currents in α-cells. Our findings show a time and concentration dependency for the malathion effect on the reduction of islet cell viability and indicate that pancreatic α cells are more sensitive to malathion effects on K_v currents and cell death.

Potential role of a newly AChE reactivator in the depressive-like behavior induced by malathion

AChE inhibition caused by exposure to organophosphate (OP) compounds is strongly related to behavioural disorders such as depression. Malathion is an OP that already has a relationship between its exposure and behavioural changes, although few data still have its effects in a longer exposure protocol. In addition, intoxication therapy is based on the use of atropine-oxime which still has its controversial efficacy depending on the type of compound. For this, (3Z)-5-Chloro-3-(hydroxyimino)indolin-2-one (Cℓ-HIN), a compound that has properties of isatin and oxime in its structure, have shown reactivating properties in the activity of AChE that have been added to antidepressant-like effects in rats exposed to malathion in acute protocol. In this sense, effects of Cℓ-HIN on the depressive-like behaviour and AChE activity were evaluated in a protocol of subchronic exposure to malathion in rats. Male wistar rats were co-treated with Cℓ-HIN [5 mg/kg, p.o.] and/or malathion [1 or 10 mg/kg, i.p] for 20 days. The exposure to both doses of malathion increased immobility time of rats on the forced swimming test (FST). Besides, malathion inhibited the AChE activity in the prefrontal cortex of rats, but any significant difference was observed in the hippocampus. Cℓ-HIN protected against increased immobility time in the FST of those rats exposed to a dose of 1 mg/kg of malathion. Similarly, Cℓ-HIN was able to reactivate AChE activity only in that group exposed to the lowest dose of malathion. Collectively, the results of this study suggest that Cℓ-HIN is an oxime capable of reactivating AChE inhibited and presents na antidepressant-like effect in cases of prolonged exposure to malathion.