脑微透析法研究大鼠脊髓损伤后脑内兴奋性氨基酸的动态变化

Dynamic Changes of Excitatory Amino Acid in Some Brain Areas after Spinal Cord Injury in Rats: A Microdialysis Study

目的研究大鼠脊髓损伤后大脑中枢兴奋性氨基酸水平的变化,探讨微透析技术在脊髓损伤中的应用,以及脊髓损伤与大脑中枢反应的关系。方法将Wistar大鼠分为损伤组、对照组和正常组,损伤组定位脑内纹状体,运用微透析技术检测大鼠脊髓损伤前1 h,损伤后0.5 h,2 h,6 h,24 h,72 h其脑细胞外液(ECF)兴奋性氨基酸含量的变化,选取谷氨酸含量([Glu]d)和天门冬氨酸含量([Asp]d)为兴奋性氨基酸的主要参考值。结果大鼠脊髓损伤0.5 h后脑内[Glu]d和[Asp]分别为损伤前基础值的(402±10)%、(642±7)%(P<0.01),然后逐步回落,于伤后24 h大致恢复正常。结论由于谷氨酸,天门冬氨酸是大脑内重要的兴奋性氨基酸递质,因此脊髓损伤后脑内兴奋性氨基酸水平的一过性升高提示大脑皮质、脑干网状结构正常状态对脊髓易化作用在脊髓损伤后所依赖的神经递质水平受到显著影响,而且微透析技术可以较好地检测其动态变化。

Objective To explore the regional change after spinal cord injury（SCI） and study the potential of microdialysis in monitoring the concentration changes of excitatory amino acid in extracellular fluid after SCI. Methods The probe of microdialysis was to collect content of excitatory amino acid in some brain areas 1 h before injury and 0.5 h, 2 h, 6 h, 24 h, 72 h after injury, then they were measured. Results Both amino acid level of experiment animals significantly increased 0.5 h after SCI, especially Glu concentration was increased to（402±10）% of the baseline and Asp concentration to（642 ±7） % of the baseline. And then appeaed to decline at the 6 th, and at the 24 th returned to the normal valure approximately. Conclusion The present finding suggests that spinal Cord damage might influence brain aminoacids level significantly, and microdialysis is a good way to do monitoring.