Developmental neurotoxicity of sarin and soman in guinea pigs

描述（由申请方提供）：发育中的哺乳动物中枢神经系统（CNS）对有机磷（OP）神经毒剂的敏感性以及常用的急性OP毒性解毒剂（如阿托品和解磷定）在孕妇和发育中的胎儿中的安全性迄今尚不清楚。例如，在1995年东京地铁沙林恐怖袭击事件中，出现轻度OP中毒症状后寻求医疗的孕妇没有得到任何治疗。最近关于沙林在鸟类模型中的神经行为致畸性的报告强调了研究OP神经毒剂的发育神经毒性的紧迫性。近年来，加兰他敏，一种目前被批准用于治疗阿尔茨海默病的药物，成为新生儿，青春期前和成年豚鼠急性OP中毒的有效解毒剂。加兰他敏治疗也被证明可以抵消青春期前豚鼠单次暴露于0.6-1.0xLD50梭曼后数月出现的认知缺陷和焦虑样行为。因此，本项目的目的是测试中心假设，即发育中的哺乳动物中枢神经系统对神经毒剂沙林和梭曼非常敏感，加兰他敏或阿托品将是有效的医学对策，对这些药物的发育神经毒性。豚鼠将是首选的动物模型，因为：（i）豚鼠的大脑发育与人类和非人类灵长类动物的大脑发育非常相似，（ii）与人类一样，豚鼠的循环羧酸酯酶水平较低-这种酶可以代谢CNOOP化合物。该项目的近期目标是：（i）确定产前暴露于梭曼或沙林对豚鼠神经行为以及大脑功能，结构和代谢完整性的影响，以及（ii）评估 加兰他敏或阿托品在与人类使用相容的剂量下对抗神经毒剂的发育毒性的安全性和有效性。妊娠豚鼠将在关键妊娠期（GD 50-52）接受皮下注射溶剂或给定剂量（0.6 x或1.0 x LD 50）的梭曼或沙林。随后（1或24小时后），用生理盐水（0.5 ml/kg，肌肉注射）或临床相关剂量的加兰他敏（8 mg/kg，肌肉注射）或阿托品（0.5 mg/kg，肌肉注射）处理母猪。在出生后第35-40天（青春期前）和第120-125天（成年初期），将分析动物的认知和情感行为。为了检查产前暴露于神经毒剂对脑电活动的影响，在行为测试之前将遥测脑电图活动。磁共振成像和光谱学将用于识别大脑结构和代谢的偏差。这些转化的多学科研究的结果将具有深远的意义，因为它们将为推进旨在确定安全有效的治疗策略的研究奠定必要的基础，即使是在沙林和梭曼恐怖袭击事件中治疗最敏感的人群。

DESCRIPTION (provided by applicant): The sensitivity of the developing mammalian central nervous system (CNS) to organophosphorus (OP) nerve agents and the safety of antidotes such as atropine and pralidoxime, commonly used against acute OP toxicity, in pregnant women and the developing fetuses are hitherto unknown. Thus, during the 1995 terrorist attack with sarin in the Tokyo subway, pregnant women who sought medical attention after presenting mild signs of OP intoxication received no therapeutic treatment. The urgency of studies to investigate the developmental neurotoxicity of OP nerve agents is underscored by the recent report of the neurobehavioral teratogenicity of sarin in an avian model. In recent years, galantamine, a drug currently approved to treat Alzheimer's disease, emerged as an effective antidote against acute OP poisoning in neonatal, prepubertal, and adult guinea pigs. Treatment with galantamine was also shown to counteract the cognitive deficits and anxiety-like behavior seen months after a single exposure of prepubertal guinea pigs to 0.6-1.0xLD50 soman. The present project is, therefore, aimed at testing the central hypothesis that the developing mammalian CNS is exquisitely sensitive to the nerve agents sarin and soman and that galantamine or atropine will be effective medical countermeasures against the developmental neurotoxicity of these agents. The guinea pig will be the animal model of choice because: (i) brain development of guinea pigs closely resembles that of humans and non-human primates and (ii) like humans, guinea pigs have low levels of circulating carboxylesterases - the enzymes that metabolically inactivate OP compounds. The immediate goals of this project are: (i) to identify the effects of a prenatal exposure to soman or sarin on neurobehavior as well as functional, structural, and metabolic integrity of the brain of guinea pigs, and (ii) to assess the safety and effectiveness of galantamine or atropine, at doses that are compatible with human use, to counter the developmental toxicity of the nerve agents. Pregnant guinea pigs will receive, at a critical gestational period (GD 50-52), a subcutaneous injection of vehicle or a given dose (0.6x or 1.0xLD50) of soman or sarin. Subsequently (1 or 24 h later), the sows will be treated with saline (0.5 ml/kg, im) or a clinically relevant dose of galantamine (8 mg/kg, im) o atropine (0.5 mg/kg, im). On postnatal days 35-40 (prepuberty) and 120-125 (young adulthood), cognitive and emotional behavior of the animals will be analyzed. To examine the effects of the prenatal exposure to the nerve agents on electrical brain activity, electroencephalographic activity will be telemetrically monitored prior to the behavioral tests. Magnetic resonance imaging and spectroscopy will be used to identify deviations in brain structure and metabolism. The results of these translational, multidisciplinary studies will be far reaching as they will laythe groundwork necessary to advance research aimed at identifying safe and effective therapeutic strategies to treat even the most sensitive sector of the population in the event of a terrorist attack with sarin and soman.