Effect of prenatal exposure to acetaminophen during critical period of brain growth spurt on exploratory and cognitive behavior: Guinea pig model

摘要 止痛剂对乙酰氨基酚（N-乙酰基-对氨基苯酚; Tylenol®，APAP）的推荐剂量为 一直被认为对孕妇是安全的，直到流行病学研究报告说， 暴露于APAP的人有很高的风险患上一些神经系统疾病，包括注意力- 缺陷/多动障碍（ADHD）和自闭症谱系障碍（ASD）。然而，重要的是要注意， 这些研究没有建立产前APAP暴露与 儿童神经系统疾病另一方面，临床前研究表明，小鼠和 大鼠在其新生期的大脑生长突增导致认知缺陷， 在成年早期的神经行为障碍。不幸的是，人类大脑的时间发展 与小鼠或大鼠的大脑不同。因此，关于妊娠期暴露是否 APAP导致胎儿大脑发育中断，从而损害神经行为功能 在以后的生活中仍然没有答案。在这里，我们建议使用豚鼠作为动物模型的选择， 测试中心假设，产前暴露于APAP在大脑生长突增期， 对情绪和认知行为的长期、性别依赖性影响， 大脑的电活动和/或结构完整性。豚鼠是一种独特的动物模型， 因为它的胎盘结构，大脑发育的时间进程，以及APAP代谢过程中， 妊娠期与人类相似。一种涉及行为分析的多学科方法， 脑电图（EEG）和免疫组织化学（IHC），以及安慰剂对照、随机、盲态 设计，最大限度地减少实验偏差和最大限度地提高科学严谨性将用于解决两个具体的 目标。在目标1中，实验将确定豚鼠经口出生的雄性和雌性后代是否 在胎脑的妊娠关键期用APAP（50-100 mg/kg，每天两次，共10天）处理 生长突增表现出探索、社交和/或认知行为受损。这些是行为领域 与产前APAP暴露儿童相关的神经系统疾病受损。结束时 行为测试中，动物将用于目标2中设计的实验，以确定产前是否 暴露于APAP会引起脑电活动的显著改变，这是在遥测EEG中测量的， 和/或海马体结构完整性的破坏，海马体是已知在结构上 ADHD和ASD的症状这种方法将使我们能够确定功能和结构的相关性， APAP暴露后代的行为结果。成功完成本研究将填写 关于妊娠期使用APAP安全性的知识差距。它还将为以下方面奠定基础： 未来的研究旨在确定APAP暴露在不同环境下对发育的影响， 怀孕的各个阶段以及这些影响的分子机制。

ABSTRACT Recommended doses of the analgesic acetaminophen (N-acetyl-p-aminophenol; Tylenol®, APAP) were presumed to be safe for pregnant women until epidemiological studies reported that children prenatally exposed to APAP are at high risk of developing a number of neurological disorders, including attention- deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). It is important to note, however, that these studies did not establish a cause-consequence relationship between prenatal APAP exposure and childhood neurological disorders. Preclinical studies, on the other hand, have shown that exposure of mice and rats to APAP during their neonatal period of brain growth spurt causes cognitive deficits among other neurobehavioral impairments in early adulthood. Unfortunately, the temporal development of the human brain does not parallel that of the mouse or the rat brain. Therefore, the question as to whether gestational exposure to APAP causes disruption of fetal brain development and, thereby, compromises neurobehavioral functions later in life remains unanswered. Here, we propose to use the guinea pig as the animal model of choice to test the central hypothesis that prenatal exposure to APAP during the period of brain growth spurt has long-term, sex-dependent effects on emotional and cognitive behavior that correlate with disruption of the electrical activity and/or structural integrity of the brain. The guinea pig is a unique animal model, because its placental structure, the temporal course of its brain development, and APAP metabolism during pregnancy closely resemble those of humans. A multidisciplinary approach involving behavioral assays, electroencephalography (EEG), and immunohistochemistry (IHC), and a placebo-controlled, randomized, blind design that minimizes experimental bias and maximizes scientific rigor will be used to address two specific aims. In Aim 1, experiments will determine whether male and female offspring born from guinea pigs orally treated with APAP (50-100 mg/kg twice a day for 10 days) during the gestational critical period of fetal brain growth spurt present impaired exploratory, social, and/or cognitive behavior. These are behavioral domains impaired in neurological disorders associated with prenatal APAP exposure of children. At the end of the behavioral test, animals will be used in the experiments designed in Aim 2 to determine whether the prenatal exposure to APAP causes significant alterations of the electrical brain activity, measured in telemetric EEG, and/or disruption of the structural integrity of the hippocampus, a brain region critical known to be structurally disrupted in ADHD and ASD. This approach will enable us to identify functional and structural correlates of the behavioral outcomes in APAP-exposed offspring. Successful completion of this study will fill in the knowledge gap regarding the safety of gestational use of APAP. It will also lay the groundwork for future studies aimed at identifying the effects of developmental effects of APAP exposure at different stages of pregnancy and the molecular mechanisms underlying these effects.