食蟹猴脑缺血过程中皮层谷氨酸水平动态变化的研究

Dynamic changes of glutamate during cerebral ischemia in the cortex of cynomolgus monkeys

目的探讨食蟹猴脑缺血过程中皮层细胞外谷氨酸水平动态变化。方法取3只(7.3±1.5)岁的食蟹猴,将大脑中动脉(middle cerebral artery,MCA)M1段近端夹闭1 h后放开,建立食蟹猴脑缺血性模型,并通过磁共振成像检查(MRI)、神经功能缺损评分评价临床表现。在MCA M1夹闭前、夹闭过程中、夹闭放开后和术后第1、2周于手术同侧大脑皮层运动区同一部位,运用电化学微电极传感器技术检测该部位谷氨酸水平。结果短期夹闭MCA M1段的食蟹猴大脑皮层运动区谷氨酸水平在MCA M1夹闭过程中较夹闭前上升(P=0.003);夹闭放开后较夹闭过程中的变化差异无统计学意义(P=0.877);术后第1周较夹闭放开后下降(P=0.004);术后第2周较术后第1周的变化差异无统计学意义(P=0.085)。结论脑缺血时可能加速皮层细胞外谷氨酸的释放,再灌注后谷氨酸的释放可能有所减弱或处于动态平衡。

Objective To explore the dynamic changes of glutamate in the cortex of cynomolgus monkeys during cerebral isehemia. Methods Proximal M1 segment of middle cerebral artery （MCA） was occluded for 1 h in 3 young cynomolgus monkeys （7.3 ± 1.5 years old） to induce cerebral isehemia. Magnetic resonance imaging and neurologic deficit scoring were used to evaluate the ischemia and observe the manifestations, respectively. Fast Analytical Sensing Technology （FAST） was applied to record the content of cortex glutamate in the same site of ipsilateral primary motor cortex in the periods of pre-, during, and post- occlusion, and at 1 and 2 weeks after surgery. Results Compared with pre-oeclusion, the content of glutamate was increased significantly in the process of occluding in the MCA M1 （ P= 0. 003 ） ; No significant difference was observed in the content during occluding and post-occlusion （P= 0. 877）. The content in the first week was decreased obviously as compared with post-occlusion （P = 0. 004）, but it showed no statistical difference with that in the second week （P = 0. 085 ）. Conclusion Cerebral ischemia may potentially accelerate the extra-cellular glutamate release in the cortex, but reperfusion may ameliorate or balance off the glutamate release.