神经元型一氧化氮合酶基因在脑震荡大鼠脑组织中的表达

背景脑震荡是一种轻型颅脑损伤,因其客观指标较少,常为临床诊断和治疗带来难度.在基础研究方面,脑啡肽和多巴胺在其中的表达及其意义尚不清楚.目的探讨神经元型一氧化氮合酶(neuronnitric oxide synthase,nNOS)在大鼠实验性脑震荡中的表达及意义.设计随机对照实验研究.地点和对象实验地点解放军军事医学科学院放射医学研究所.健康Wistar雄性二级(清洁级)大鼠80只,军事医学科学院实验动物中心清洁级动物房饲养,水料任意,用于复制脑震荡动物模型,依致脑震荡所用砝码质量不同,随机分为对照组,50,100,200g组.主要观察指标实验动物于伤后1,3,7,14及30 d活杀取脑组织,经免疫组化和原位杂交等技术研究nNOS在脑震荡中的变化规律.结果100g组见典型脑震荡的临床表现,其病理改变为脑血管扩张,脑组织瘀血、水肿,神经元变性、坏死,尼氏体减少甚至消失.nNOS蛋白和mRNA于伤后3d表达增强,7 d达高峰,14 d后开始减少,30 d仍呈阳性表达.阳性部位见于大脑皮质、海马、丘脑和小脑神经元胞浆内.结论脑震荡以血液循环障碍和实质细胞变性、坏死为主要病理改变;nNOS基因表达参与脑震荡发生时脑组织损伤的病理过程,可能对神经细胞变性、坏死起重要调节作用.

Expression of neuronalnitric oxide synthase gene in the brain tissue of rats with cerebral concussion

BACKGROUND: Cerebral concussion is a mild brain injury. In basic researches, the expression and significance of enkaphalin and dopamine in cerebral concussion remain poorly understood.OBJECTIVE: To observe the expression of neuronal nitric oxide synthase (nNOS) gene in rat models of cerebral concussion and to explore its significance.DESIGN: A randomized controlled trialled study.SETTING and PARTICIPANTS: This study was conducted in the Institute of Radiation Medicine, Academy of Military Medical Sciences. Rat models of cerebral concussion was established in 80 healthy male Wistar rats of clean grade purchased from the Experimental Animal Center of Academy of Military Medical Sciences with free access to food and water. The rats were randomly divided into 4 groups according to the different levels of cerebral impact for model establishment, namely the control group, 50, 100 and 200 g counterweight groups.MAIN OUTCOME MEASURES: Brain tissue samples were taken 1, 3, 7,14 and 30 days after injury respectively, from each group, to examine the changes in the expression of nNOS gene in the course of cerebral concussion by means of immunohistochemistry and in situ hybridization.RESULTS: Rats in 100 g group exhibited typical manifestations of cerebral concussion as seen in the clinical setting. The pathological changes included cerebral vascular dilatation, congestion, edema of the cerebral tissues, neuronal degeneration, necrosis, and decrease or even disappearance of the Nissl bodies. The protein and mRNA of nNOS were increased 3 days after the injury, peaked on the 7th day, and decreased till the 14th days but still remained positive on the 30th day. The positive expression was detected in the plasma of neurons in the cerebral cortex, hippocampus, thalamus and cerebellum.CONCLUSION: Cerebral concussion is pathologically characterized by blood circulation disorder and neural cell degeneration and necrosis. The expression of nNOS gene participates in brain tissue damage in cerebral concussion, and may play an important role in regulating neural cell degeneration and necrosis.