3种大鼠全脑缺血模型定量脑电图的实验研究

Use of quantitative EEG in models of whole cerebral ischemia in rats

目的 比较正常大鼠不同电极联接方式的脑电图的差异 ,并以脑电图作为判定指标 ,评价 3种全脑缺血大鼠模型的缺血效果。方法 应用皮层电极和头皮电极分别描记正常大鼠双顶叶脑电图 ,比较 2种不同联接方式其结果的差别 ;分别应用四血管阻断法 (4VO)、两血管阻断加低血压法 (2VO)和颈动脉负压分流法 (CNPS)制作大鼠全脑缺血模型 ,观察其脑电图形态和各波段相对功率值的变化。结果 皮层电极脑电图的波幅较头皮电极的波幅高 ,但其形态及相对功率值与头皮电极无明显差别 ;4VO组和CNPS组在缺血早期即出现α波相对功率值的大幅度下降和θ波相对功率值的增高 ,而 2VO组上述改变出现较晚。结论 脑电图应用于全脑缺血动物模型缺血程度和速度的判断时 ,头皮电极可以替代皮层电极。 4VO组和CNPS组缺血时间较早 ,缺血完全 ;但 4VO的缺血程度不稳定 。

Objective To compare the results of electroencephalograph (EEG) with the electrode applied in different ways and to evaluate the three models of whole cerebral ischemia in rats using EEG as the indicator. Methods EEG of bilateral parietal lobes was recorded in 2 groups of normal rats with the electrodes applied into the cortex and subcutaneous tissue respectively. The EEG recorded in different ways were compared. Three models of whole cerebral ischemia in rats were induced by means of four-vessel occlusion (4VO), carotid negative pressure shunt (CNPS) and two-vessel occlusion plus low blood pressure (2VO) respectively. The features of the EEG recorded in the three models were compared. Results The wave amplitude of EEG from cortex electrode was higher than that from subcutaneous electrode. But their forms and relative power had no difference. Significant rise of α wave and decrease of θwave were observed in the early stage of ischemia in the 4VO group and CNPS group, and relatively late in the 2VO group. Conclusion When EEG was used to evaluate the cerebral ischemia in animal models, the subcutaneous electrode can well be used to substitute for the cortex electrode. The cerebral ischemia starts earlier in 4VO and CNPS groups than in 2VO group. But the degree of cerebral ischemia in 4VO group is not as steady as that in CNPS group.