慢性应激对ADHD模型动物HPA轴的影响及龙牡桂枝汤的干预机制研究

Attention deficit hyperactivity disorder（ADHD）is the most common childhood psychological and behavior disorders caused by genetic and environmental factors.It was found to be associated with hypothalamic-pituitary-adrenal (HPA) axis and chronic stress,and the chronic stress can lead to abnormal structure and function of HPA axis, the interaction between HPA axis and chronic stress may have an important impact on the onset of ADHD.Based on the previous research, the study centres on HPA axis and chronic stress,ADHD animal model SHR(spontaneously hypertensive rat) and its normal control WKY (wistar kyoto rat) are taken as the experimental animals.Chronic unpredictable mild stress (CUMS) is used to simulate the stress responses under various environmental and psychological stress factors.Around CRH signaling pathway and GC feedback regulation circuit which reflect the process of HPA axis activity,the changes of HPA axis in experimental animals under CUMS are observed by ethology, pathological morphology, cell and molecular biology methods. Based on the above results,the research will explore the influence of the effective compound Longmuguizhi decoction on the behavior and the HPA axis of experimental animals, aim to investigate the role of environmental and psychological factors in the occurrence and development of ADHD, and to demonstrate the relationship between the mechanism of drug action and the pathogenesis of ADHD.The study will help to reveal the scientific connotation of compound prescription in the treatment of ADHD, provide theoretical and experimental basis for finding new drug targets, and it also provide a new ideas for the prevention and treatment of ADHD with Traditional Chinese Medicine.

注意缺陷多动障碍（ADHD）是由遗传和环境不良因素共同作用的儿童最常见心理行为障碍性疾病。研究发现HPA轴和慢性应激与本病存在关联，而慢性应激可导致HPA轴异常，二者间的交互作用可能对ADHD的发病有重要影响。据此，本课题在前期研究基础上，以HPA轴和慢性应激为切入点，以ADHD模型动物SHR大鼠及其正常对照WKY大鼠为研究对象，以慢性不可预知温和应激（CUMS）模拟多种环境和心理因素作用下的应激反应，围绕反映HPA轴活动始末的CRH信号传递通路和GC反馈调节环路，通过行为学、病理形态学、细胞及分子生物学方法，多层次探索慢性应激状态下大鼠行为和HPA轴的变化，在此基础上观察有效复方龙牡桂枝汤对大鼠行为及HPA轴的影响，以探讨环境及心理因素在ADHD发生发展中的作用，阐释药物作用机制与ADHD发病机制间的相关性，为探索新的药物作用靶点提供理论依据和实验基础，为中医药防治ADHD提供新思路。

注意缺陷多动障碍（ADHD）是儿童最常见的心理行为障碍性疾病。研究发现HPA轴和慢性应激与本病相关，而慢性应激可导致HPA轴异常，二者间的交互作用可能对ADHD的发病有重要影响。本课题以HPA轴和慢性应激为切入点，以ADHD模型动物SHR大鼠及其正常对照WKY大鼠为研究对象，以慢性不可预知温和应激（CUMS）模拟多种环境和心理因素作用下的应激反应，通过行为学、病理形态学、ELISA、实时定量PCR和免疫组化法，探究慢性应激状态下大鼠行为和HPA轴的变化，观察有效复方龙牡桂枝汤对大鼠行为及HPA轴的影响，以探讨环境及心理因素在ADHD发生发展中的作用，阐释药物作用机制与ADHD发病机制间的相关性。.本研究发现，与WKY大鼠相比，SHR大鼠血清CORT、ACTH水平明显下降（P＜0.01），血清CRH水平明显增高（P＜0.01），下丘脑及海马GR、MR　mRNA和蛋白存在高表达（P＜0.01），而下丘脑CRH　mRNA和蛋白表达较低（P＜0.01）。SHR大鼠和WKY大鼠在接受3周慢性不可预知温和应激后，自发活动减少（P＜0.01），在Morris水迷宫实验中寻找平台的潜伏期明显延长，进入平台象限次数减少（P＜0.01），海马形态结构呈现器质性改变，血清CORT、CRH、ACTH水平均明显增高（P＜0.01），海马GR表达明显下降，MR 表达明显增加（P＜0.01），下丘脑CRH、CRH-BP，CRHR1及垂体CRH-BP，CRHR1的表达增高（P＜0.01）。SHR大鼠通过盐酸哌甲酯和龙牡桂枝汤干预，WKY大鼠通过龙牡桂枝汤干预后，寻找平台的时间变短，在目标象限的时间和穿越平台的次数增加（P＜0.01），血清CORT、ACTH、CRH水平明显降低（P＜0.01）。下丘脑CRH、CRHR1、CRH-BP及垂体CRHR1和CRH-BP表达下降，海马中GR表达升高、MR表达下降（P＜0.01）。.结论：SHR大鼠HPA轴呈低反应性，可能与CRH启动障碍及下丘脑和海马GR、MR高表达相关。慢性应激可致SHR大鼠和WKY大鼠HPA轴功能亢进及海马损伤，使其学习记忆能力下降，但未发现可诱发多动行为。龙牡桂枝汤可通过减少下丘脑CRH、CRHR1、CRH-BP及垂体CRHR1和CRH-BP表达，调控海马中GR和MR的表达，改善HPA轴功能，提高慢性应激状态下SHR大鼠的学习记忆能力。