NMDA受体Ⅰ及白细胞介素-1在癫痫机制中的作用

The effects of NMDA receptor 1 and interleukin 1 on the pathogenesis of epilepsy

应用北京医科大学培育的听源性癫痫易感大鼠Ｐ７７ＰＭＣ，以癫痫不易感大鼠Ｗｉｓｔａｒ为对照，系统研究了ＮＭＤＡ受体亚单位Ⅰ（ＮＲ１）与白细胞介素１（ＩＬ１）在癫痫发生发展中的作用及相互关系。实验在整体、脑片、神经细胞培养及分子水平进行。所得较有意义的结果如下：（１）在听源性惊厥易感大鼠Ｐ７７ＰＭＣ整个发育过程中脑内ＮＲ１ｍＲＮＡ的表达，以及成年鼠脑内ＮＭＤＡ受体活性（ＭＫ８０１结合）都高于对照组Ｗｉｓｔａｒ大鼠。惊厥后Ｐ７７ＰＭＣ脑内ＮＲ１ｍＲＮＡ的表达呈时间依赖性增加，惊厥后２４ｈ比惊厥前增加１１１％～２０２％；ＮＲ１反义寡核苷酸脑室注射（每μｌ１０μｇ）可显著减轻Ｐ７７ＰＭＣ大鼠惊厥程度，并可对谷氨酸引起的体外神经细胞的损伤有保护作用，抑制谷氨酸导致的神经毒性作用。由此证实ＮＲ１参与惊厥的发生发展，并与Ｐ７７ＰＭＣ大鼠的遗传性癫痫易感性关系密切。（２）在神经细胞培养中ＩＬ１β可明显剂量依赖性地（１～２５Ｕ·ｍｌ１）提高ＮＲ１ｍＲＮＡ的表达，白细胞介素１受体拮抗剂（ＩＬ１ｒａ）可阻断此效应；ＩＬ１β可剂量依赖性地提高ＮＲ１受体活性，因此提示ＩＬ１具有兴奋性神经调质的作用，其作?

Using audiogenic epilepsy prone rat P77PMC matched with epilepsy resistant Wistar rat, we systematically studied the effects of NMDA receptor I (NR 1) and interleukin 1 (IL 1) on the pathogenesis of epilepsy. Experiments were conducted in vivo , in brain slice, neuronal cell cultures, and at molecular levels. Some meaningful results were summarized as follows:(1) In P77PMC rat brain, NR 1 gene expression during development, and NMDA receptor activity (MK 801 binding) in adult rat were higher than that of control. After seizures, in adult P77PMC rat brain, NR 1 mRNA expression showed time dependently up regulation, above the basal level 111%-202% at 24 hours. Intracerebral ventricular (i.c.v) injection of NR 1 antisense oligonucleotide (10 μg per μl) significantly reduced P77PMC rat audiogenic seizure severity. Pretreatment NR 1 oligonucleotide (2 μmol·L -1 ) to neuronal cell cultures, inhibited neuronal glutamate damage. So we considered NR 1 participated in seizure pathogenesis, and closely related to the seizure susceptibility of P77PMC rat.(2) IL 1β can dose dependently (1-25 U·ml -1 ) increase NR 1 mRNA expression, and augment NR 1 activity in neuronal cell cultures; IL 1 receptor antagonist (IL 1ra) can reverse the effects of IL 1β. SoIL 1 acts as an excitatory neuromodulator, may be due to its direct or indirect effects on increasing NR 1 gene expression and NR function of the brain.(3) Using defective herpes simplex virus 1 (HSV 1) vector pHSVLac(kindly donated by Dr. Geller, Harvard University) successfully constructed recombinant pHSV IL 1ra vector, to study experimental transgenic expression of IL 1ra. I.c.v. injection of pHSV IL 1ra pseudovirus (5×10 5 pfu) can significantly inhibit seizure attacks of P77PMC; the transgenic expression of IL 1ra mRNA and protein in related brain regions can be maintained longer than 6 weeks.