皮层电刺激联合康复治疗对大鼠脑缺血皮层运动区突触超微结构及结构参数的影响

Ultrastructure Changes and Texture Parameters Analyses of the Synapses in Rats of Cortical Electrical Stimulation Combined with Rehabilitative Training Following Focal Cortical Ischemia

目的探讨皮层电刺激联合康复锻炼对大鼠脑缺血皮层运动区突触超微结构的影响。方法选取成年健康雄性清洁级SD大鼠30只,在大鼠训练模具中进行单个食粒抓取训练,训练7 d后记录大鼠的优势爪,训练共持续14 d,14 d后连续3 d测定每只大鼠抓取食粒成功率。纳入标准要求连续3 d抓取食粒成功率至少高于30%,共有18只大鼠入组。参照大鼠脑立体定位图谱定位脑运动区,将内皮素注射到大脑中动脉的起始点附近,阻断大脑中动脉的供血区域,制造大鼠脑梗死模型,并在相应运动皮层硬膜外放置刺激电极。脑梗死模型建立后,大鼠随机分为刺激组和对照组,每组9只,进行14 d的康复治疗:刺激组大鼠在电刺激的同时进行单个食粒抓取功能锻炼;对照组大鼠只进行单个食粒抓取功能锻炼。康复治疗14 d后对大鼠进行灌注取脑,取大鼠梗死灶周围皮层,电镜下观察突触超微结构改变,应用Image J图像分析软件,对选定的突触超微结构参数,即突触数量及突触间隙宽度等进行分析。结果①术后大鼠共死亡5只,死亡原因考虑为术后感染。②术前两组大鼠抓取成功率差异无统计学意义(P>0.05),康复治疗后刺激组大鼠抓取成功率高于对照组[(31.8±8.5)%vs(18.1±4.4)%,P=0.021]。③采用Image J软件进行电镜图像分析,结果显示刺激组大鼠脑缺血皮层运动区突触数量较对照组增多[(0.0520±0.0383)个/μm^3 vs(O.0387±0.0315)个/μm^3,P=0.022]。两组间突触间隙宽度差异无统计学意义(P>0.05)。结论皮层电刺激联合康复治疗较单纯康复治疗能够促进大鼠脑梗死灶周围皮层运动区突触数量增加,增强了突触超微结构的可塑性。

Objective To explore the ultrastructure and texture parameters changes of the synapses due to cortical electrical stimulation combined with rehabilitative training following focal cortical ischemia in rats.Methods Thirty rats reached for single food pellets in a box made of clear plexiglas. When the success rate was more 30% in three consecutive days, rats were admitted. There were eighteen rats into the group and the skilled forelimb was recorded after seven days training.Locating the brain motor area by the rat brain stereotactic atlas, and then Endothelin was injected into the starting point of the middle cerebral artery to block the blood supply of the middle cerebral artery to make infarction rat model. And then put the stimulating electrode outside the scleromeninx corresponding infarct. After operation, rats were randomly divided into two groups：stimulating group received cortical electrical stimulation combined with rehabilitative training; control group, only the rehabilitative training, which last for two weeks. The ultrastucture changes of the synapses were observed with electron microscopy. The number of synapses and Width of synaptic cleft were studied with image analysis.Results ①There were three death after operation due to postoperative infection; ②There was no statistical significance between the two groups before operation（P=0.144）. The stimulation group had significantly greater rates of improvement with the impaired forelimb in comparison to control group（P=0.021）. ③Image J software using electron microscopy image analysis results showed that stimulation of cerebral ischemia in rat motor cortex than in the control group increased the number of synapses, a statistically significant difference（P〈0.05）. Width of synaptic cleft was no significant difference between the two groups（P〉0.05）.Conclusion Cortical electrical stimulation combined with rehabilitative training following focal cortical ischemia can promote synaptic growth and enhancs plasticity of synaptic structure, thus contributing to the rehabilitation of the hemiplegic limb function.