Department of Diagnostic Radiology & Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, United States.
Neurotoxicology. 2013 May;36:42-8. doi: 10.1016/j.neuro.2013.02.002. Epub 2013 Feb 11.
This study was designed to test the hypothesis that in vivo magnetic resonance imaging (MRI) and spectroscopy (MRS) can detect in adulthood the neurotoxic effects of a single exposure of prepubertal guinea pigs to the organophosphorus pesticide chlorpyrifos. Twelve female guinea pigs were given either a single dose of chlorpyrifos (0.6×LD50 or 300mg/kg, sc) or peanut oil (vehicle; 0.5ml/kg, sc) at 35-40 days of age. One year after the exposure, the animals were tested in the Morris water maze. Three days after the end of the behavioral testing, the metabolic and structural integrity of the brain of the animals was examined by means of MRI/MRS. In the Morris water maze, the chlorpyrifos-exposed guinea pigs showed significant memory deficit. Although no significant anatomical differences were found between the chlorpyrifos-exposed guinea pigs and the control animals by in vivo MRI, the chlorpyrifos-exposed animals showed significant decreases in hippocampal myo-inositol concentration using MRS. The present results indicate that a single sub-lethal exposure of prepubertal guinea pigs to the organophosphorus pesticide chlorpyrifos can lead to long-term memory deficits that are accompanied by significant reductions in the levels of hippocampal myo-inositol.
体内磁共振成像（MRI）和光谱（MRS）可在成年期检测到幼年豚鼠单次接触有机磷杀虫剂毒死蜱的神经毒性作用。12 只雌性豚鼠在 35-40 天大时接受了单次剂量的毒死蜱（0.6×LD50 或 300mg/kg，sc）或花生油（载体；0.5ml/kg，sc）。暴露一年后，动物在 Morris 水迷宫中进行测试。在行为测试结束后的三天，通过 MRI/MRS 检查动物大脑的代谢和结构完整性。在 Morris 水迷宫中，暴露于毒死蜱的豚鼠表现出明显的记忆缺陷。尽管体内 MRI 未发现暴露于毒死蜱的豚鼠与对照动物之间存在明显的解剖差异，但 MRS 显示海马肌醇浓度明显降低。目前的结果表明，幼年豚鼠单次接触亚致死剂量的有机磷杀虫剂毒死蜱可导致长期记忆缺陷，同时海马肌醇水平显著降低。
