大鼠脑缺血不同时期躯体感觉诱发电位的研究

脑电信号（EEG）具有较高的时间分辨率、可观测脑内活动的动态变化、完全无损检测等优点，常用于对神经系统疾病的诊断，本研究探讨脑缺血后躯体感觉诱发电位（SEP）变化及大脑皮层的功能恢复。利用线栓法建模成功的25只SD雄性大鼠分为5组，分别为正常对照组和左侧中动脉缺血术后4、24、 48 h和1周4个实验组。采用SEP记录法，在术后不同时间段电刺激大鼠的右前爪正中神经支配区，记录对照组和实验组左侧皮层脑电信号，提取SEP，并对安静状态下的脑电进行频谱分析，定量评价左侧中动脉缺血后初级体感皮层SEP及功率谱变化过程。实验结果显示，术后4 h，SD大鼠左侧大脑皮层测得的SEP潜伏期较正常状态显著增大（（16.0±1.1）ms vs（33.7±1.3）ms，P<0.01），波幅变小（（197.2±13.0）μV vs（25.1±2.0）μV，P<0.01），θ波、α波、β波、γ波的能量明显变小。θ波：（139 367.86±178.66）μV^2vs（2.22±0.40）μV²，P <0.01；α波:（5389.33±25.55）μV² vs（0.23±0.01）μV²，P<0.01；β波：（7911±416）μV² vs（0.01±0.01）μV²，p<0.01； γ波：（0.30±0.12）μV² vs（0.00±0.00）μV²，P<0.01。随着术后时间的延长，上述特征与对照组的差距逐渐缩小，但还不能达到正常状态的水平。研究提示，SEP可在一定程度上反映脑缺血大鼠大脑皮层功能的变化。

Somatosensory Evoked Potential Changes in a Rat Model of Cerebral Ischemia

The electroencephalogram (EEG) is often applied to diagnose the diseases of the nervous system because of its advantages of high time resolution, clear observation to the dynamic changes for the brain activity, and the completely non invasive detection. To explore somatosensory evoked potential (SEP) changes and functional recovery of the cerebral cortex following cerebral ischemia, 25 Sprague Dawley male rats have been divided into 5 groups, which include control group and four ischemia groups， 4 h group, 24 h group, 48 h group and 1 w group. The rat model of cerebral ischemia has been established by middle cerebral artery occlusion (MCAO) in the left hemisphere. SEP of left cortex was detected by electrically stimulating the right median nerve of rat paw. The EEG in resting state was analyzed by spectral technology. The result shows that， after 4 hours of MCAO the latency of SEP has been significantly prolonged（（16.0±1.1）ms vs（33.7±1.3）ms，P<0.01）, and the amplitude is decreased（（197.2±13.0）μV vs（25.1±2.0）μV，P<0.01）. The energy of θ wave, α wave, β wave, γ wave are significantly smaller. θ wave:（139 367.86±178.66）μV² vs（2.22±0.40）μV²，P <0.01；α wave:（5 389.33±25.55）μV²   vs（0.23±0.01）μV²，P <0.01；β wave:（7911±4.16）μV² vs（0.01±0.01）μV²，P<0.01；γ wave:（0.30±0.12）μV² vs（0.00±0.00）μV²，P <0.01. With the extension of time after operation, the difference of these characteristics between control group and ischemia group has been reduced gradually (P <0.01). However, these characteristics cannot reach the normal. This indicates that SEP can be used to evaluate the function of cerebral cortex in rats with cerebral ischemia in a certain extent.