Subchronic neurotoxicity of chlorpyrifos, carbaryl, and their combination in rats

Abstract

Anticholinesterase pesticides have been widely used in agricultural and domestic settings and can be detected in the environment after long-term use. Although the acute toxic effects of chlorpyrifos and carbaryl have been well described, little is known about the chronic toxicity of the pesticides mixture. To investigate their chronic neurotoxicity, Wistar rats were exposed to chlorpyrifos, carbaryl, and their mixture (MIX) for 90 consecutive days. The activities of serum cholinesterase (ChE) as well as acetylcholinesterase (AChE) and neuropathy target esterase (NTE) in nerve tissues were determined. Furthermore, the histopathological examination was carried out. The results showed that ChE activity significantly decreased in all treated rats except the rats treated with low dose carbaryl. Treatment with middle- and high-dose chlorpyrifos and MIX in rats significantly inhibited AChE activity in the central nervous tissues, whereas treatment with carbaryl alone did not. In sciatic nerve, AChE activity was significantly inhibited by high-dose carbaryl and MIX, but not by chlorpyrifos alone. No significant NTE inhibition was observed in all treatment groups. Histopathological examination revealed that both chlorpyrifos and MIX treatment induced hippocampal damage. However, no obvious hippocampal damage was found in carbaryl-treated rats. Carbaryl and MIX, but not chlorpyrifos alone, induced pathological damage of sciatic nerve. Taken together, all of the results indicated that chlorpyrifos and carbaryl have different toxicological target tissues in nervous system and showed corresponding effects in the nervous tissues, which may reflect the different sensitivity of central and peripheral nervous tissues to different pesticides individually and in combination.

Chronic low back pain among tobacco farmers in southern Brazil

“…29,31 Specific neurotoxic effects of organophosphates on the sciatic nerve have been found in rats and hens. 32 The same effect was found in frogs exposed to pyrethroids. 33 However, the question we used to measure pesticide poisoning was generic and subject to recall bias.…”

Metabolomic analysis for combined hepatotoxicity of chlorpyrifos and cadmium in rats

“…Since organisms are often exposed to multiple xenobiotics, it is important to study their combined toxicity. In addition, more and more studies suggest that simultaneous exposure to different xenobiotics can potentiate the toxicity of individual chemicals (Corbel et al, 2006;Banni et al, 2011;Wang et al, 2014). The acute and subchronic toxicity of CPF and Cd in the liver has been well characterized (Goel et al, 2005;Acker et al, 2012;Borges et al, 2008;Elsharkawy et al, 2013;Meggs and Brewer;.…”

“…CPF can inhibit acetylcholinesterase activity and induce cholinergic neurotoxicity (Marty et al, 2012;Wang et al, 2014).…”

Extractive spectrophotometric method for the determination of carbaryl in environmental samples

“…The acute oral LD 50 for rats is 850 mg/kg [4]. It has been reported that carbaryl causes alteration of liver microsomal enzymes, neurotoxicity, immunotoxic effects, histopathological changes in the testis, haemoatopoietic alterations [5][6][7][8][9]. The extensive use of this insecticide poses a serious risk to both the environment and the human health due to direct exposure or through residues in the food and drinking water [10].…”