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

摘要 扑热息痛(N-乙酰-对氨基酚；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胎儿期出生 暴露在APAP中的人患上一系列神经疾病的风险很高，包括注意力- 缺陷/多动障碍(ADHD)和自闭症谱系障碍(ASD)。然而，必须指出的是， 这些研究没有建立产前APAP暴露和 儿童期神经性障碍。另一方面，临床前研究表明，暴露于小鼠和 大鼠在其新生儿期的脑生长爆发期给予APAP会导致认知障碍等 成年期早期的神经行为障碍。不幸的是，人脑的时间发育 无法与老鼠或大鼠的大脑相提并论。因此，孕期接触的问题是 APAP会导致胎儿大脑发育中断，从而损害神经行为功能 晚年的生活仍然没有答案。在这里，我们建议使用豚鼠作为选择的动物模型 检验核心假设，即在大脑生长突发期产前暴露于APAP会 长期的性别依赖对情绪和认知行为的影响，与精神障碍相关 大脑的电活动和/或结构的完整性。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在 怀孕与人类非常相似。一种涉及行为分析的多学科方法， 脑电(EEG)、免疫组织化学(IHC)和安慰剂对照、随机、盲法 最大限度地减少实验偏差和最大限度地提高科学严谨性的设计将用于解决两个具体的 目标。在目标1中，实验将确定从豚鼠口中出生的雄性和雌性后代 胎脑妊娠关键期应用APAP(50~100 mg/kg，每日2次，共10天)治疗 生长突发期表现为探索性、社交和/或认知行为受损。这些是行为域 在与产前接触APAP相关的神经疾病中受损的儿童。在结束时， 行为学测试，将动物用于目的2设计的实验，以确定是否产前 暴露在APAP中会导致遥测EEG测量的大脑电活动发生显著变化， 和/或破坏海马体的结构完整性，这是一个关键的大脑区域，从结构上讲 在ADHD和ASD中受到干扰。这种方法将使我们能够确定 暴露于APAP的子代的行为结果。成功完成这项研究将填写 关于妊娠使用APAP的安全性的知识差距。它还将为以下方面奠定基础 未来的研究旨在确定不同年龄段APAP暴露对发育的影响 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.