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目的观察剧毒杀鼠剂四次甲基二砜四胺(tetramine,TET)所致顽固性癫痫(refractory epilepsy,RE)大鼠大脑皮质NMDA受体亚单位在染毒后不同时间的表达变化,研究NMDA受体亚单位表达与TET诱发癫痫及由此引发脑损伤的相关性。方法建立TET(0.4 mg/kg,ig)所致大鼠RE及脑损伤模型,采用实时荧光定量PCR及Western印迹技术,测定RE动物大脑皮质NMDA受体不同亚型在染毒后不同时间mRNA及蛋白水平的表达变化。结果大鼠TET染毒10～25 min后即出现RE,染毒后24 h,其大脑皮质出现明显病理学改变。NR2A的mRNA及蛋白表达水平在皮质出现病理学改变前即显著降低(P<0.01),至染毒后72 h,尚未恢复正常水平(P<0.01);NR2B蛋白水平的表达在病理学改变出现前未见显著性改变,至染毒后72 h,表达显著降低(P<0.01);但其mRNA水平在整个观测时间点未见显著性改变。结论 TET所致RE可诱发NMDA亚单位NR2A及NR2B表达下调,NR2A表达下调可能与RE发生及由此引发脑损伤的关系更为直接。
Objective To observe the changes of NMDA receptor subunits in the cerebral cortex of rats with refractory epilepsy (RE) induced by tetramine (TET) To investigate the relationship between NMDA receptor subunit expression and TET-induced epilepsy and the consequent brain injury. Methods The model of RE and brain injury induced by TET (0.4 mg / kg, ig) was established. Real-time fluorescent quantitative PCR and Western blotting were used to detect the mRNA and protein levels of different subtypes of NMDA receptor in RE animals Changes in protein expression. Results RE occurred after 10-25 min exposure to TET in rats, and obvious pathological changes appeared in cerebral cortex 24 h after exposure. The mRNA and protein expression of NR2A decreased significantly (P <0.01) before the pathological changes of the cortex and did not return to the normal level at 72 h (P <0.01). The expression of NR2B protein appeared in pathological changes No significant changes were found before 72 h, and the expression was significantly decreased at 72 h (P <0.01). However, the mRNA level did not change significantly at the whole observation time. Conclusion RE induced by TET is down-regulated in NR2A and NR2B subtypes. The down-regulation of NR2A expression may be directly related to the occurrence of RE and the consequent brain injury.