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Optical measurement of brain oxygen tension during cerebral ischemia and reperfusion

脑缺血和再灌注过程中脑氧分压的光学测量

基本信息

批准号：
13671453
负责人：
ITOH Toshiyuki
金额：
$ 1.79万
依托单位：
Kyoto Prefectural University of Medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13671453/
关键词：
microcirculation oxygen tension oxygen transport ischemia reperfusion cerebral circulation arteriole venule 白血球粘着

项目摘要

The measurement of oxygen tension (PO_2) in the brain is quite important in the study of ischemic diseases. To date, most PO_2 measurements have been performed using oxygen microelectrodes. However, the microelectrode is not always a suitable tool for studying brain oxygenation because insertion of the electrode into the brain per se causes hemorrhage and hence leads to erroneous PO_2 measurement. Furthermore, microelectrodes only measure PO_2 in the brain surface as epifluorescent microscopic patterns, using the oxygen-sensitive fluorescent membrane technique with proper modificationsAn oxygen-quenching fluorescence dye, tris (1,10-phenanthroline) ruthenium (II) chloride hexahydrate, was immobilized in silica-gel beads 3 um in diameter and the dyed heads were embedded in a highly gas-permeable (〜20 um thick), opaque silicone-rubber film formed on a microscope coverslip. Unlike the original method, intended for transparent mesenteric tissue, he opaque silicone elastomer was adopted to … More minimize the effect of the redox state of the brain tissue on the optical measurement of PO_2. The feasibility of this technique for use in brain microcirculatory studies was assessed using Pulsinelli's four-vessel occlusion rat. Under pentobarbital anesthesia (35 mg/Kg. I.p.), male wistar rats (300-350g, n=8) underwent bilateral electrocauterization of the vertebral arteries. After 24 hours recovery, two cranial windows were made in the skull under anesthesia (15% urethane, 10 ml/Kg, s.c.) and the oxygen-sensitive membrane was placed on the brain, with the PO_2-sensing side in very gentle contactwith the brain surface through one cranial window. Under artificial ventilation, the animals were subjected to occlusion of the common carotid arteries, which resulted in reversible brain ischemia as monitored by a Laser-Doppler flowmeter through the other window. During the ischemia/reperfusion periods, the fluorescence pattern on the oxygen-sensitive membrane was video-recorded continuously and subjected to subsequent playback analysis and conversion to PO_2 valuesThe present method enabled us to visualize the PO_2 gradient on the rat brain surface without causing cortical injury. In ischemia/reperfusion protocol, heterogeneity in the PO_2 distribution on the brain surface was detected, in particular between the periarteiolar region and other regions, and this heterogeneity was observed to increase in association with ischemia Less

脑内氧分压（PO_2）的测定在缺血性疾病的研究中具有重要意义。迄今为止，大多数PO_2的测量都是用氧微电极进行的。然而，微电极并不总是一个合适的工具，用于研究脑氧合，因为电极插入脑本身引起出血，从而导致错误的PO_2测量。此外，微电极仅测量脑表面的PO_2作为落射荧光显微图案，使用氧敏感荧光膜技术，并进行适当的修改。（1，10-菲咯啉）氯化钌（II）六水合物固定在直径为3 μ m的硅胶珠中，染色的头部嵌入高度透气的（约20 μ m厚），在显微镜盖玻片上形成的不透明硅橡胶膜。与最初用于透明肠系膜组织的方法不同，采用了不透明硅胶弹性体， ...更多信息减少脑组织氧化还原状态对PO_2光学测量的影响。使用Pulsinelli的四血管闭塞大鼠评估该技术用于脑微循环研究的可行性。在戊巴比妥麻醉（35 mg/Kg. I.p.），雄性Wistar大鼠（300- 350 g，n=8）进行双侧椎动脉电灼。在24小时恢复后，在麻醉（15%氨基甲酸乙酯，10 ml/Kg，s.c.）将氧敏膜置于脑表面，氧敏侧通过一个颅窗与脑表面轻轻接触。在人工通气下，使动物经受颈总动脉闭塞，这导致可逆性脑缺血，如通过激光多普勒流量计通过另一窗口监测的。在缺血/再灌注期间，连续记录氧敏感膜上的荧光模式，并进行回放分析和转换为PO_2值。本方法使我们能够在不造成皮层损伤的情况下，观察到大鼠脑表面的PO_2梯度。在缺血/再灌注过程中，脑表面PO_2分布存在不均一性，尤其是动脉周围区与其它脑区之间，这种不均一性随着缺血时间的延长而增加。