腦缺血/灌流過程沙鼠大腦皮質區氫氧自由基、葡萄糖、丙酮酸、乳酸與麩胺酸之變化

腦中風是一種死亡率和致殘率極高的疾病，也是現今醫療保健重要的研究課題之一。腦中風對神經的損傷主要原因包括能量代謝異常、鈣離子超載、興奮性氨基酸中毒、自由基損傷等。本研究是以沙鼠腦中風動物模式進行實驗，利用微透析取樣，偵測腦缺血過程腦部大腦皮質區氫氧自由基、葡萄糖、丙酮酸、乳酸與麩胺酸的變化，同時以 3,4-dihydroxybenzoic acid ( 3,4-DHBA ) 校正活體透析的回收率。微透析樣品應用高效液相層析電化學系統偵測 3,4-DHBA 及 2, 3-DHBA 的變化，另外以微透析生化分析儀偵測樣品中葡萄糖、丙酮酸、乳酸與麩胺酸的變化，並同時以 3,4-DHBA 的改變，校正腦缺血實驗過程中氫氧自由基、葡萄糖、丙酮酸、乳酸與麩胺酸的變化。實驗結果顯示，在沙鼠腦缺血/灌流實驗過程中，回收率的變化在缺血時降至最低，而對側的回收率則無明顯變化。經回收率校正後，在腦缺血時氫氧自由基有明顯上升，葡萄糖在腦缺血時低降，灌流後逐漸回升；丙酮酸在腦缺血時低降，灌流後逐漸回升；乳酸在灌流時上升；麩胺酸在腦缺血時有明顯上升， 灌流後逐漸回復。總之，本研究方法提供偵測腦缺血實驗過程中，氫氧自由基、葡萄糖、丙酮酸、乳酸與麩胺酸的確實變化，對於探討活體動物生理變化提供了動態的數據，有助於往後腦缺血治療研究的評估。

Stroke is a common, devastating neurological disorder and one of the leading causes of death. It is also a major cause of long-term disability. Several mechanisms implicated in causing neuronal damage, there are loss of energy substrates and excitotoxic glutamate efflux and build-up of intracellular calcium and generation of reactive oxygen species (ROS) etc. Focal cerebral ischemia was induced in anesthetized gerbils by the occlusion of the right common carotid artery and the middle cerebral artery for 60 minutes and followed by 120 minutes reperfusion .The microdialysis probes were inserted into the cortex of the gerbil to monitor extracellular hydroxyl radical, glucose, lactate, pyruvate and glutamate during cerebral ischemia and reperfusion periods. The perfusion solution contains salicylic acid to trap hydroxyl radicals and 3,4-dihydroxybenzoic acid to calibrate the probe recovery.Dialysates were assayed in the microbore high-performance liquid chromatograph / electrochemical detector for the determinations of DHBAs, and microdialysis analyzer for the determination of glucose, pyruvate, lactate and glutamate .Changes of these analysis were calibrated according to the probe recovery. The present study demonstrated probe recovery decreased 48 % during cerebral ischemia. Hydroxyl radical increased 300 % whereas ischemia / reperfusion, glucose and pyruvate decreased 55 % and 85 % , lactate and glutamate increased 151% and 1395 % during cerebral ischemia.The present study provided corrected information on dynamic chemical changes following acute focal cerebral ischemia.