[Neurobehavioral assessment and brain acetylcholinesterase levels in rats subchronically exposed to fipronil]

ABSTRACT Fipronil is a selective-toxicity insecticide widely used in agriculture and veterinary medicine. However, there are reports of neurotoxic effects of this substance, causing damages to vertebrates. We evaluated the locomotor activity, motor coordination and the activity of brain acetylcholinesterase in rats exposed to fipronil. Adult male Wistar rats (n= 15) received fipronil at a dose of 30mg/kg orally for 15 days; the Control group (n= 15) was treated with oral solution in the same period. On the 16th day of experimentation, the animals were submitted to the open field arena test and hole-board test. On the 17th day, they were anesthetized and euthanized, and organs were collected, and subsequently brain AChE was evaluated. Exposure to fipronil yielded no significant changes on motor coordination and locomotor activity but caused significant inhibition of brain acetylcholinesterase activity. These findings suggest that fipronil may cause short-term neurotoxic effects, which may be exacerbated if exposure is prolonged.摘要 氟虫腈（Fipronil）是一种广泛应用于农业与兽医学领域的选择性毒性杀虫剂。已有研究报道该物质可引发神经毒性效应，对脊椎动物造成损伤。本研究针对暴露于氟虫腈的大鼠，评估其自发活动、运动协调能力及脑内乙酰胆碱酯酶（acetylcholinesterase, AChE）活性。实验选用成年雄性Wistar大鼠，分为两组：给药组（n=15）以30mg/kg的剂量经口灌胃给予氟虫腈，连续处理15天；对照组（n=15）同期给予等量口服溶剂。实验第16天，对所有大鼠开展敞箱实验（open field arena test）与洞板实验（hole-board test）。实验第17天，对大鼠实施麻醉并处死，采集脑组织后检测脑内AChE活性。结果表明，氟虫腈暴露未对运动协调能力与自发活动造成显著影响，但可显著抑制脑内乙酰胆碱酯酶活性。上述研究结果提示，氟虫腈可能引发短期神经毒性效应，若延长暴露时长则可能加剧该毒性。