Goudarzvand Mahdi, Choopani Samira, Shams Alireza, Javan Mohammad, Khodaii Zohreh, Ghamsari Farhad, Naghdi Naser, Piryaei Abbas, Haghparast Abbas
Department of Physiology and Pharmacology, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran.
Department of Physiology and Pharmacology, Pasteur Institute, Tehran, Iran.
Basic Clin Neurosci. 2016 Jan;7(1):63-72.
Memory and cognitive impairments are some of devastating outcomes of Multiple Sclerosis (MS) plaques in hippocampus, the gray matter part of the brain. The present study aimed to evaluate the intrahippocampal injection of Ethidium Bromide (EB) as a simple and focal model to assess cognition and gray matter demyelination.
Thirty Wistar rats were divided into three groups: control group, which received saline, as solvent of EB, into the hippocampus; and two experimental groups, which received 3 μL of EB into the hippocampus, and then, were evaluated 7 and 28 days after EB injection (n=10 in each group), using a 5-day protocol of Morris Water Maze (MWM) task as well as Transmission Electron Microscopy (TEM) assay.
Seven days after EB injection, the behavioral study revealed a significance increase in travelled distance for platform finding in the experimental group compared to the control group. In addition, the nucleus of oligodendrocyte showed the typical clumped chromatin, probably attributed to apoptosis, and the myelin sheaths of some axons were unwrapped and disintegrated. Twenty-eight days after EB injection, the traveled distance and the time spent in target quadrant significantly decreased and increased, respectively in experimental groups compared to the control group. Also, TEM micrographs revealed a thin layer of remyelination around the axons in 28 days lesion group.
While intracerebral or intraventricular injection of EB is disseminated in different parts of the brain and can affect the other motor and sensory systems, this model is confined locally and facilitates behavioral study. Also, this project could show improvement of memory function subsequent to the physiological repair of the gray matter of the hippocampus.
记忆和认知障碍是多发性硬化症（MS）斑块在海马体（大脑灰质部分）产生的一些毁灭性后果。本研究旨在评估海马体内注射溴化乙锭（EB）作为一种简单的局灶性模型，以评估认知和灰质脱髓鞘情况。
30只Wistar大鼠分为三组：对照组，向海马体注射作为EB溶剂的生理盐水；两个实验组，向海马体注射3μL EB，然后在注射EB后7天和28天进行评估（每组n = 10），采用为期5天的莫里斯水迷宫（MWM）任务以及透射电子显微镜（TEM）检测。
EB注射后7天，行为学研究显示，与对照组相比，实验组寻找平台的游动距离显著增加。此外，少突胶质细胞核显示出典型的染色质凝聚，可能归因于细胞凋亡，并且一些轴突的髓鞘被解开并解体。EB注射后28天，与对照组相比，实验组的游动距离显著减少，而在目标象限花费的时间显著增加。此外，TEM显微照片显示，在28天损伤组中，轴突周围有一层薄的髓鞘再生。
虽然脑内或脑室内注射EB会扩散到大脑的不同部位，并可能影响其他运动和感觉系统，但该模型局限于局部，便于进行行为学研究。此外，该项目可以显示出海马体灰质生理修复后记忆功能的改善。
