摘要
目的:Netrin-G2是一种主要在中枢神经系统表达的神经轴突导向因子,在轴突的形成及神经细胞的迁移中发挥作用。本实验通过拟通过检测Netrin-G2在耐药性癫痫患者及氯化锂-匹罗卡品大鼠癫痫模型脑组织中的表达,探讨其在耐药性癫痫发生发展中的作用。
方法:按随机化原则从课题组前期建立的耐药性癫痫患者脑组织库中抽取35例颞叶组织作为实验组,15例因外伤导致颅内高压行减压术患者的颞叶组织作为对照组。56只SD成年大鼠腹腔注射氯化锂-匹罗卡品诱导慢性颞叶癫痫大鼠模型,并于成功建立模型后分别于6小时、1天、2天、7天、14天、30天和60天各时间点随机抽取8只大鼠处死,取其海马及邻近皮质作为实验组;8只腹腔注射生理盐水的SD成年大鼠作为对照组。分别采用免疫组化、免疫荧光双标和Western-blot方法检测上述样本脑组织中Netrin-G2的表达。
结果:Netrin-G2在正常人及大鼠脑组织中主要分布于神经细胞胞浆及胞膜。耐药性癫痫患者脑组织中Netrin-G2含量较对照组显著增高。动物模型中Netrin-G2主要集中表达在齿状回、CA1和CA3区,实验组中的表达高于对照组:动物点燃后6小时开始增高,约2天达到高峰,并维持较高表达量,持续到1-2月时下降至对照组水平。
结论:在耐药性癫痫患者和动物模型中,神经轴突导向因子Netrin-G2在实验组的表达量比对照组升高,提示其可能参与了耐药性癫痫形成的病理过程,可能在异常的轴突发育及神经细胞迁移中起着重要作用,参与了异常兴奋性突触重构和病理性神经网络重组,是耐药性癫痫耐药性形成的可能原因。
The membrane-bound axon guidance molecule Netrin-G2 is preferentially expressed in the central nervous system and plays a role in synapse formation and maintenance. Using immunohistochemistry, immunofluorescence, and western blotting, we investigated the possible correlation between Netrin-G2 expression and intractable epilepsy (IE) using surgical samples from epilepsy patients. We used 35 samples of temporal neocortex from patients undergoing surgery for drug-refractory epilepsy and 15 autopsy samples from individuals who died in traffic accidents (i.e., samples of normal human brain). We also examined Netrin-G2 expression in the hippocampus and adjacent cortex of rats with temporal lobe epilepsy (lithium chloride-pilocarpine model). Netrin-G2 was expressed in the membrane and cytoplasm of neurons from control specimens, and expression was higher in tissue from patients with intractable epilepsy. Western blotting of rat brain tissue showed that Netrin-G2 was upregulated starting at 6 h after kindling. Maximal expression was seen around 2 days, and relatively high expression was maintained until 30 days. Expression then returned to normal levels at 60 days, which was consistent with the immunohistochemical and immunofluorescence results. These data implicate Netrin-G2 in the pathophysiology of epilepsy and are consistent with the hypothesis that this protein may participate in the abnormal development of synapses and in neuron migration.
引文
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