实验性大鼠脑出血后运动诱发电位和内囊区血流量的改变

Changes of motor evoked potential an d capusar blood flow following exper imental cerebral hemorrhage in rats

目的观察大鼠实验性脑出血后皮层运动诱发电位(MEP)和内囊血流量的变化,以了解大鼠脑出血致肌痉挛模型中锥体束的功能情况。方法采用大鼠自体血缓慢注入右侧内囊后肢制备大鼠脑内囊出血致肌痉挛模型,应用电生理学方法检测皮层运动诱发电位,应用氢清除法观察内囊血流量的改变,以判断上运动神经元兴奋性及传导功能的变化。结果大鼠右侧内囊出血后右侧MEP波幅较左侧显著降低(P<0.01),出血1d以后右侧MEP波幅较出血前均显著降低(P<0.01);MEP潜伏时右侧显著延长,与左侧比较差异有非常显著性意义(P<0.01),内囊出血1d以后MEP潜伏时均明显延长,与出血前比较差异有显著性意义(P<0.01)。脑出血后第1天,右侧内囊血流量有明显降低,低于伤前水平和左侧第1天内囊血流量(P<0.05)。结论内囊定向的脑出血模型引起明显的内囊损伤侧MEP波幅明显降低、潜伏时延长,一定程度上反映了皮质脊髓束的损伤情况和功能状态,以及内囊血流量恢复较快,这些可能与大鼠脊髓内踏步中枢模式发生器有关。

Objective To study the conducti on of pyramidal tract,changes of motor evoked poten tials and capsular blood flow were ob-served following experimental cere bral hemorrhage.Methods The arter ial blood from rat tail arte ry was slowly injected into the hindl imb of the ri ght capsule,which induced pyramidal tract to damage,and the rat sp astic model of capsular hemiplegia w as produced.MEPs were recorded from the gastrocnemius muscle,capsular blood flow was measure d with hydrogen clear method.Results F ollowing the right cap-sule-orientated hemorrhage the amp litude of motor evok ed potential for the right sensorimotor cortex was ob viously decreased in contr ast with those for the left(P<0.01),the latencies of MEP for the right s e nsorimotor cortex were significant ly elongated in comparison with those for t he left(P<0.01),moreover,the latencies for the rig ht after 1day post-hemorrhage were m arkedly prolonged as compared with pre-hemorrhage(P<0. 01).At the first day after capsular hemo rrhage,the blood flow for the righ t i nternal capsule was significantly d ecreased compared with levels for pre-i njury(P<0.05)and for left capsular blood flow at th e same time (P<0. 05).Conclusion Cap-sule-orientated hemorrhage may induce the amplitude of MEP for the injur ed side decreases obviously and the l atencies of MEP elongate d .These show the functional state and i njured condition for corticospinal tra ct to a certain degree.The capsul ar blood flow and behavior resume quickly in despite of corticospinal tract injured ,this may be involved i n stepping cent er pattern generators in spinal cord in rats.