成年大鼠全臂丛根性撕脱伤后对侧运动皮层可塑性变化的实验研究

目的 探讨成年大鼠全臂丛根性撕脱伤后不同时间段对侧运动皮层的可塑性变化。方法 将30只SD雄性大鼠分为6组，即正常对照组和全臂丛根性撕脱伤术后1d、7d、1个月、3个月、1年共5个时间组，每组5只。采用皮层内微电极电刺激技术，定量评价大鼠左前肢代表区内的可塑性变化。结果 术后不同时间组在原前肢代表区内可诱发出不同的运动类型，包括左侧胡须、下颌、颈部和左下肢4个部位点的运动，但只有颈部位点自始至终占据着术前前肢代表区。结论 成年大鼠的运动皮层仍具有可塑性，术后对侧运动皮层在术前前肢代表区发生了功能重组，并且这种功能重组是动态变化的。瘫痪肢体以上最临近部位的肌肉控制力其代偿性明显增强。

Experimental study on changes of plasticity of contralateral motor cortex following total brachial plexus root avulsion injuries in the adult rats

ObjectiveTo investigate changes of plasticity of contralateral mo tor cortex at different intervals following total brachial plexus root avulsion injuries in adult rats. MethodsTotal left brachial plexus root avulsion injury model was set up in 25 male Sprague-Dawley rats. They were divided into 5 gro u ps according to different intervals of examination, including 1 day, 7 days, 1 m onth, 3 months and 1 year groups. Another 5 rats without surgery served as the normal control group. Intracortical microstimulation was used to quantitatively evaluate the changes of plasticity of the corresponding left forelimb motor regi on. ResultsVarious types of movement were evoked in the left f orelimb represe ntation region throughout the entire period after the innervating nerves were di sconnected. However, the sites of neck firmly occupied the left forelimb represe ntation region throughout the entire process.ConclusionThe mot or cortex of a dult rats still had the ability of plasticity. Dynamic functional reorganization took place in the forelimb representation region of the contralateral primary m otor cortex following disconnection of the brachial plexus. The control strength of the muscles above the paralyzed muscles was significantly enhanced in compen sation.