异氟醚预处理对大鼠脑缺血再灌注损伤细胞内游离钙的影响

目的: 观察异氟醚对缺血再灌注大鼠活体脑片细胞内游离钙的影响,探讨异氟醚脑保护作用的机制。方法: 采用线栓法阻闭大鼠大脑中动脉造成局灶性脑缺血,并于缺血2h后拔出栓线给予再灌注。利用细胞内钙离子荧光探针Fluo-3AM在激光共聚焦显微镜下观察再灌注2h后大鼠脑片细胞内荧光强度。比较异氟醚预处理1h对缺血再灌注大鼠活体脑片额顶叶皮质及纹状体区域Ca²⁺浓度的影响。结果: 缺血再灌注损伤大鼠缺血侧脑片皮层及纹状体Ca²⁺荧光强度明显升高。脑缺血前给予异氟醚预处理1h可抑制缺血侧大脑皮层细胞内Ca²⁺含量的增加,对纹状体细胞内Ca²⁺含量的影响无统计学差异。结论: 缺血前给予异氟醚预处理可有效减轻额顶叶皮层细胞内的钙超载,对纹状体区域脑细胞内游离钙水平影响较小,提示异氟醚的脑保护作用在不同脑区存在差异。

Effects of isoflurane pretreatment on changes of intracellular calcium in cerebral ischemic reperfusion injury in rats

AIM: To investigate the changes of intracellular calcium concentration in vital brain slices after pretreatment with isoflurane in cerebral ischemic reperfusion rats.METHODS: Focal cerebral ischemia was induced by inserting a suture into the middle cerebral artery of rats.Reperfusion was accomplished by withdrawing the suture after 2 hours'ischemia.The changes of intracellular calcium in vital brain slices were determined by fluorescent Ca²⁺-indicator fluo-3 AM.The effects of isoflurane pretreatment were evaluated before cerebral ischemia on the intracellular calcium of cortex and striatum.RESULTS: Intracellular calcium concentration increased significantly both in the cortex and the striatum of the brain after cerebral ischemia reperfusion.Isoflurane pretreatment given before cerebral ischemia inhibited the elevation of Ca²⁺in the cortex but not in the striatum induced by ischemia reperfusion injury.CONCLUSION: Isoflurane can inhibit Ca²⁺overloading in cortex induced by cerebral ischemia reperfusion, which may be one of the mechanisms of isoflurane neuroprotection.