核磁共振检测大鼠早期癫痫源性脑损伤的动态发展特征

为探讨癫痫源性脑损伤形成早期不同脑区病理改变和行为发作的动态发展特征 ,本研究对大鼠右背侧海马 (hippocampus,HPC)施加慢性强直电刺激 (6 0Hz,2s,0 .4～ 0 .6mA)诱发癫痫发作 ,1次 /d。每天记录大鼠原发性湿狗样抖动 (wetdogshakes,WEDS)频率 ,分别对大鼠施加电刺激 2、4、6、8和 10d后进行核磁共振成像 (T2 weightedmagneticresonanceimage ,T2 WI)检测 ,并对鼠脑进行了组织学切片鉴定。结果表明 :与空白对照组相比较 ,(1)施加 2d强直电刺激时 ,大鼠双侧背部侧脑室 (lateralventricle,LV)区域呈现对称性T2 WI信号绝对值增加 (n =4,左侧P =0 .0 0 18;右侧P =0 .0 0 10 ) ;施加 6d强直电刺激时 ,大鼠呈现植入电极对侧中、腹部LV区域T2 WI信号值增加 (n =5 ,P =0 .0 0 73;P =0 .0 2 49) ;施加 8d强直电刺激后 ,大鼠仅出现植入电极对侧腹部LV区域T2 WI信号值增加 (n =3,P =0 .0 34 0 ) ;施加 10d强直电刺激后 ,大鼠植入电极同侧腹部LV区域T2 WI信号值增加 (n =4,P =0 .0 10 7) ;(2 )随着强直电刺激天数增加 ,大鼠原发性WEDS频率高峰期出现在第 4个刺激日 ,然后WEDS频率下降 ,与T2 WI信号强度增加之间呈高度负相关关系 (相关系数r =- 0 .987,P <0 .0 2 ) ;(3)组织学切片鉴定 :T2 WI检测LV信号异

Development and progression in rat brain abnormalities related to early stage of epilepsy measured by magnetic resonance image

The purpose of the present study was to investigate the features of pathophysiological neural networks in rat temporal lobe epileptogenesis. To establish electrogenic epilepsy model, repetitive tetanization (60 Hz, 2 s, 0.4-0.6 mA) was delivered into the right dorsal hippocampus (HPC) of rat brain. Rats were divided into different groups. Experimental animals received tetanic stimulation once a day for 2, 4, 6, 8 or 10 days, respectively. Primary wet dog shakes (WEDS) of the animals were recorded daily during the stimulation to understand the development of behavioral seizures at early stage of epilepsy. The T(2)-weighted (T(2)-WI) spin-echo images were obtained from each experimental rat. The results demonstrated that T(2)-WI hyperintensity of experimental rats was observed in bilateral symmetric dorsal lateral ventricle (LV) areas at stimulating day 2 (n=4), in contralateral medial and ventral LV areas to the side of the electrode at stimulating day 6 (n=5), in contralateral ventral LV areas at stimulating day 8 (n=3), and in ipsilateral ventral LV areas at stimulating day 10 (n=4). Therefore the peak rate of primary WEDS appeared on stimulating day 4 in the experimental rats. Morphological identification demonstrated that the T(2)-WI signal abnormalities were related to the enlarged LV and pathological ventricular choroidea plexus hyperplasia. The results suggest that the development of rat brain abnormalities from dorsal LV to ventral LV at early stage of epilepsy can be measured by magnetic resonance image, which implies reorganization of pathophysiologically functional networks before kindling effect appear.