颞叶癫大鼠海马区NCX3 mRNA和蛋白的表达变化

目的:动态观察钠-钙交换体(NCX)mRNA和蛋白在氯化锂-匹罗卡品致模型大鼠海马CA1、CA3及齿状回区表达的变化,探讨其在癫发生发展中的作用。方法:用氯化锂-匹罗卡品制备癫动物模型;应用原位杂交和免疫组化技术检测各时间点NCX3mRNA和蛋白的表达。结果:急性期(6～24h)海马各区NCX3mRNA表达均随时间的延长逐渐减少;进入静止期各区表达趋向回升,慢性反复自发发作期(30、60d)各区表达又出现不同程度的两次下调。除致后6h大鼠海马各区的NCX3蛋白表达无明显变化外,NCX3蛋白变化趋势与NCX3mRNA基本一致。结论:NCX3表达下调可能通过增加神经元钙超载,改变海马神经元的兴奋性,促使癫发生。

Altered Expression of Na~+-Ca~(2+) Exchanger Isoform NCX3 mRNA and Protein in Hippocampus of Temporal Lobe Epileptic Rat

Aim: To investigate the expressions of Na+-Ca2+ exchanger isoform NCX3 mRNA and protein in the dentate gyrus, CA1, CA3 regions by hippocampus of lithium-pilocarpine induced epileptic rat. Methods: The models of epilepsy were established by injecting pilocarpine and lithium. The NCX3 mRNA and protein were quantitatively analyzed at different time by using in situ hybridization and immunohistochemistry. Results: Expression of NCX3 mRNA in the hippocampus had significant decreases at 6 h, 12 h and 24 h after seizures, then increased slowly to normal level. However, at 30 d and 60 d, a second dramatic decrease was found in NCX3 mRNA expression. The change tendency of NCX3 protein was similar to NCX3 mRNA, except the protein did not increase at 6 h. Conclusion: The decreased expression of NCX3 in hippocampus might increase the overloading of free intracellular calcium and change the excitability of hippocampal neurons to induce seizures.