title: 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.
authors: Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichenxi Road, Beijing 100101, People's Republic of China.
authors: Hui-Ping
authors: HP
authors: Wang
authors: Yu-Jie
authors: YJ
authors: Liang
authors: Ying-Jian
authors: YJ
authors: Sun
authors: Wei-Yuan
authors: WY
authors: Hou
authors: Jia-Xiang
authors: JX
authors: Chen
authors: Ding-Xin
authors: DX
authors: Long
authors: Ming-Yuan
authors: MY
authors: Xu
authors: Yi-Jun
authors: YJ
authors: Wu
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D012721:Carbaryl / Q000633:toxicity*; D004390:Chlorpyrifos / Q000633:toxicity*; D002800:Cholinesterase Inhibitors / Q000633:toxicity*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D010575:Pesticides / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology
chemical_list: D002800:Cholinesterase Inhibitors; D010575:Pesticides; D000110:Acetylcholinesterase; D004390:Chlorpyrifos; D012721:Carbaryl
keywords: cholinesterase; combined toxicity; histopathology; neurotoxicity; pesticide; subchronic exposure