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Dentate neurogenesis and neural maturation in animal models of epilepsy

癫痫动物模型中的齿状神经发生和神经成熟

基本信息

批准号：
20591722
负责人：
NAKAJIMA Madoka
金额：
$ 2.58万
依托单位：
Juntendo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2010
项目状态：
已结题

项目摘要

【Purpose】Neuronal regeneration is thought to be induced by stimulation from ischemia or epileptic seizures, as well as to compensate for neuronal necrosis or apoptosis from such insults. It is also said that neuronal regeneration is a cause of hippocampal epileptogenesis, although much is unknown about the turnover mechanism or significance of newly formed neurons. Using an animal model in which epileptic seizures were induced by pilocarpine, changes in hippocampal neurogenesis with time brought about by epilepsy were investigated using immunostaining and electrophysiological (patch-clamp) techniques. The role of hippocampal neurogenesis in epileptogenesis was then examined.【Methods】Forty-eight hours after epileptic seizures were induced by intraperitoneal injection of pilocarpine in C57/BL mice, the hippocampus was injected with a green fluorescent protein (GFP) using a retrovirus. Thus, new nerves induced by the epileptic seizure were marked with GFP. Immunostaining was done 7 days ( … More 1 week), 14 days (2 weeks), and 28 days (4 weeks), 6 months after status epilepticus, and the degree of maturation of normal neurons (NeuN staining), DCX, NeuroD, PSA, BrdU and the proportion of apoptosis (ssDNA staining) were investigated. With the patch-clamp, the firing pattern in the cells marked with GFP was directly recorded to investigate cell excitability.【Observation results】Many new cells were produced in the subgranule zone after the epileptic seizures, but they were small and fragile, and almost none of the immature GFP-positive cells entered the maturation process. They disappeared by 1-4 weeks after the seizure. The GFP-positive cells that disappeared at an early stage were negative for both ssDNA and NeuN. The GFP-positive cells at 1-2 weeks after the seizure had input resistances (IRs) of 1.2 GΩ-2.0 GΩ and resting membrane potentials (RMPs) of -55 mV to -70 mV. The GFP-positive cells at 4 weeks had IRs of 300 MΩ-1000 MΩ and RMPs of -70 mV to -80 mV. The membrane resistance in the new neurons induced by epilepsy was higher in the less mature cells, and they had a low firing rate. Less

[目的]神经元再生被认为是由缺血或癫痫发作的刺激诱导的，以及补偿由这些损伤引起的神经元坏死或凋亡。也有人说，神经元再生是海马癫痫发生的一个原因，虽然很多是未知的周转机制或新形成的神经元的意义。使用动物模型，其中癫痫发作由毛果芸香碱诱导，海马神经发生的变化与癫痫所带来的时间进行了研究，使用免疫染色和电生理（膜片钳）技术。然后研究海马神经发生在癫痫发生中的作用。[方法] C57/BL小鼠腹腔注射匹罗卡品诱发癫痫发作后48 h，用逆转录病毒将绿色荧光蛋白（GFP）注入海马。因此，用GFP标记由癫痫发作诱导的新神经。免疫组化染色进行了7天（ ...更多信息分别于癫痫持续状态后1周、14天、28天、6个月检测正常神经元成熟度（NeuN染色）、DCX、NeuroD、PSA、BrdU及凋亡比例（ssDNA染色）。采用膜片钳技术，直接记录GFP标记细胞的放电模式，研究细胞的兴奋性。[观察结果]癫痫发作后，颗粒下区产生大量新生细胞，但体积小、易碎，几乎没有未成熟的GFP阳性细胞进入成熟过程。癫痫发作后1-4周消失。在早期阶段消失的GFP阳性细胞对ssDNA和NeuN均为阴性。癫痫发作后1-2周，GFP阳性细胞的输入电阻（IR）为1.2 GΩ ~ 2.0 GΩ，静息膜电位（RMPs）为-55 mV ~-70 mV。4周时GFP阳性细胞的IR为300 MΩ-1000 MΩ，RMP为-70 mV至-80 mV。癫痫诱导的新生神经元的膜电阻在较不成熟的细胞中更高，并且它们具有较低的放电频率。少