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

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3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±8.3）% 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/μm3 vs （0.0387±0.0315）个/μm3,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。     

小剂量纳洛酮协同麻黄碱对脑缺血大鼠神经可塑性的影响

目的 研究小剂量纳洛酮协同麻黄碱对动物运动功能恢复的影响,并通过对缺血周围区皮质GAP-43、SYP的检测,进一步探讨麻黄碱加速运动功能恢复的分子机制.方法 雄性SD大鼠,采用Koizumi线栓法制备大鼠大脑中动脉闭塞（MCAO）模型,缺血2h后再灌注.分假手术组、自然恢复组、麻黄碱组、纳洛酮＋麻黄碱组、纳洛酮组.术后分1、2、3、4周4个时间点,横木行走试验评定运动功能改善情况;免疫组化光密度定量法观察缺血周围区生长相关蛋白（GAP-43）、突触素（SYP）表达强度.结果 横木行走试验显示麻黄碱组速度明显快于自然恢复组（P＜0.05）,而麻黄碱＋纳洛酮组明显快于麻黄碱组（P＜0.05）;前3个时间点免疫组化光密度定量测定显示麻黄碱组GAP-43、SYP的表达水平明显高于自然恢复组（P＜0.05）,而麻黄碱＋纳洛酮组明显高于麻黄碱组（P＜0.05）.结论 麻黄碱可促进大鼠脑缺血后的运动功能恢复,使GAP-43、SYP等蛋白表达增强.而小剂量纳洛酮协同麻黄碱进一步加速大鼠脑缺血后的运动功能恢复,使GAP-43、SYP表达显著增强,进一步证实提高脑内神经重塑的分子表达是麻黄碱促进神经康复的机制之一.     

脑缺血再灌注后神经可塑性的研究进展

【摘要】 大脑对缺血再灌注损伤有一定代偿修复能力,可通过多种机制发生可塑性变化。脑内与缺血再灌注有关的可塑性物质主要有突触素（synaptophysin,Syn）、生长相关蛋白-43（growthassociated protein-43,GAP-43）及微管相关蛋白-2（microtubule-associated protein-2,MAP-2）等物质,它们通过各自途径影响脑缺血再灌注后脑的可塑性变化,而可塑性变化又受到生存环境、康复训练、药物治疗等因素的影响。     

运动训练对大鼠脑缺血再灌注后神经修复及GAP-43和Neurocan表达的影响

目的 观察运动训练对大鼠脑缺血再灌注后不同时间神经修复及GAP-43与Neurocan表达的影响.方法 健康雄性Wistar大鼠72只,随机分成运动训练组、对照组、假手术组.采用线栓法制作一侧大脑中动脉闭塞(MCAO)模型,以神经功能缺损评分和Morris水迷宫试验进行神经功能评价,免疫组化法观察对脑缺血周围GAP-43与Neuorcan的表达.结果 与对照组比较,脑缺血再灌注后14d、21d,运动组的肢体运动及记忆功能明显恢复;缺血再灌注后7d,对照组缺血周围出现GAP-43阳性细胞,14d减少,21d、28d明显减少,运动组GAP-43表达在14d、21d、28d较对照组显著增加(P<0.05).Neurocan阳性细胞在对照组缺血再灌注7d出现,14d达高峰,21d、28d时下降;运动组Neurocan表达在缺血再灌注14d、21d、28d较对照组显著减少(P<0.05).结论 运动训练上调大鼠脑缺血区GAP-43表达与下调Neurocan表达,可能是其促进脑损伤区中枢神经修复的重要机制之一.     

低剂量米诺环素对脑缺血再灌注大鼠RGMa表达的影响

目的探讨静脉用低剂量米诺环素对大鼠脑缺血再灌注损伤后神经功能恢复及排斥性导向分子(repulsive guidance molecule A,RGMa)表达的影响。方法成年雄性Sprague-Dawley大鼠54只,随机分为假手术组,缺血再灌注组和米诺环素组。采用大脑中动脉线栓法制作局灶性脑缺血再灌注模型。再灌注第2周,分别采用免疫组织化学及Western blot法检测缺血脑组织内RGMa及生长相关蛋白-43(growth associated pro-tein-43,GAP-43)蛋白的表达。缺血再灌注第2、7、14和28天,采用改良的神经功能缺损评分(modified neu-rological severity score,m NSS)及楼梯实验(staircase test)评估大鼠神经功能。结果同缺血再灌注组相比,低剂量米诺环素使缺血侧大脑皮层RGMa蛋白表达降低(0.53±0.08 vs.1.17±0.15,P0.05),GAP-43蛋白表达明显增高(0.94±0.10 vs.0.57±0.09,P0.05),大鼠m NSS评分显著下降并改善大鼠的前肢运动功能(P0.05)。结论静脉用低剂量米诺环素(3 mg/kg)能促进大鼠缺血再灌注损伤后神经功能的恢复,其机制可能与下调RG-Ma蛋白及上调轴突再生相关蛋白GAP-43的表达有关。     

大鼠脑缺血再灌注后海马CA1区星形胶质细胞与突触可塑性的关系

目的 研究大鼠脑组织缺血再灌注后星形胶质细胞与GAP-43变化的关系.方法 建立局灶性脑缺血再灌注模型.72只大鼠随机分为假手术组、缺血再灌注组,在各时间点处死取脑,应用免疫组化法检测海马CA1区GFAP、GAP-43的表达.结果 不同时间点缺血再灌注组GFAP、GAP-43表达均高于同时期假手术组(P＜0.01);缺血再灌注组GFAP与GAP-43高度相关(P＜0.05).结论 脑缺血再灌注后,海马CA1区星形胶质细胞与GAP-43变化具有高度相关性.     

大鼠脑缺血再灌注损伤后GAP-43及IGF-1在神经系统中的表达

目的探讨大鼠脑缺血再灌注损伤后生长相关蛋白-43（GAP-43）和胰岛素样生长因子-1（IGF-1）的表达。方法成年健康雄性Wistar大鼠72只，随机分为GAP-43组36只和IGF-1组36只，每组再分为假手术组和缺血1h再灌注2h、6h、12h、24h、48h、3d、7d、14d组，每组4只（n=4）。应用线栓法制备大鼠脑缺血再灌注动物模型，免疫组织化学方法检测GAP-43与IGF-1在神经元中的表达。结果GAP-43组：缺血再灌注2h，皮质区、海马及纹状体区神经元GAP-43呈基础表达，6h后表达逐渐增高，7d达高峰，14d开始降低，较假手术组高（P〈0．05）。IGF-1组：缺血再灌2h IGF-1表达明显增高，24h达高峰，48h恒定表达，14d仍维持高表达，较假手术组高（P〈0．05）。结论GAP-43和IGF-1可能参与促进神经元轴突的再生。     

脑缺血再灌注损伤后GAP-43蛋白的表达和意义

目的 探讨脑缺血再灌注损伤后生长相关蛋白-43（GAP-43）的表达对神经元轴突再生的可塑性变化.方法 成年健康雄性Wistar大鼠40只,随机分为正常对照组、假手术组和缺血1h再灌注2h、6h、12h、24h、48h、3d、7d、14d组,每组各4只（n=4）.应用线栓法制备大鼠脑中动脉闭塞再灌注模型（MCAO）,采用免疫组织化学方法检测GAP-43的表达并观察神经元轴突再生的变化,并进行计算机图像分析.结果 缺血再灌注2h,海马、皮质区及纹状体区GAP-43呈基础表达,6h、12h、24h、48h表达逐渐增高,7d达高峰,P＜0.05,14d达最低表达,P＜0.05.与假手术组比较有显著性差异,P＜0.05.正常对照组无表达.缺血再灌注48h～7d损伤区域神经元轴突呈出芽征,发出突触纤维.结论 脑缺血再灌注损伤后GAP-43呈非特异性表达,并促进神经元的修复和再生.     

8溴-环磷酸腺苷对脑缺血再灌注大鼠PKA及GAP-43蛋白表达的影响

目的:观察脑室注射8-溴-环磷酸腺苷(8-B-cAMP)对脑缺血再灌注大鼠大脑皮质蛋白激酶A(PKA)及生长相关蛋白43(GAP-43)表达的影响。方法:采用线栓法制作大鼠脑缺血再灌注模型,将45只大鼠分为假手术对照组,缺血组(单纯脑缺血再灌注组)和8-B-cAMP组(脑缺血再灌注并脑室注射8-B-AMP)。用放免法测缺血周边区脑组织cAMP的含量,Westernblot(免疫印迹法)检测蛋白激酶A(PKA)及生长相关蛋白43(GAP-43)的表达。结果:脑缺血组6h、24h cAMP的含量下降,GAP-43及PKA蛋白表达减少;8-B-cAMP治疗组脑组织GAP-43蛋白表达较缺血组增加,且这种变化与cAMP的含量及PKA蛋白表达增加相一致。结论:8-B-AMP能够增加PKA及GAP-43的表达从而促进脑缺血再灌注后的轴突再生。     

大鼠大脑皮层梗死后丘脑继发性轴突变性

目的 探讨高血压大鼠大脑皮层梗死同侧丘脑腹后核（ventroposterior nucleus of the thalamus,VPN）继发性轴突变性的病理过程。方法 采用易卒中型肾血管性高血压大鼠（stroke-prone renovascular hypertensive rats,RHRSP）模型制备右侧大脑中动脉皮层支闭塞（middle cerebral artery occlusion,MCAO）模型,作为MCAO组。RHRSP模型仅暴露而不凝闭右侧大脑中动脉皮层支（middle cerebral artery,MCA）,作为假手术组。健康配对的成年大鼠,作为正常对照组。上述3组动物分别在术后1、2、4周3个时间点,行Bielschowsky氏嗜银染色及免疫组织化学染色检测梗死同侧丘脑腹后核βA4淀粉样前体蛋白（amyloid βA4 precursor protein,APP）、生长相关蛋白43（growth associated protein-43,GAP-43）和微管相关蛋白2（microtubule associated protein-2,MAP-2）的表达水平。结果 与同期假手术组相比,在梗死同侧丘脑腹后核,缺血4周时检测到嗜银染色的纤维束明显减少（P <0.05）;APP蛋白在缺血1周时表达开始增强并逐渐增高（P <0.05）,GAP-43蛋白、MAP-2蛋白的表达水平在缺血1～2周开始下降（P <0.05）并持续降低（P <0.05）。结论 轴突标志性蛋白的免疫组织化学检测方法敏感性高、能早期发现丘脑轴突的病理改变,与传统的嗜银染色方法结合,能较全面地评价VPN轴突变性的病理过程。本实验发现梗死同侧VPN的轴突变性是一个慢性进展性的过程。     

Epidural cortical stimulation enhances motor function after sensorimotor cortical infarcts in rats

This study examined whether epidurally delivered cortical electrical stimulation (CS) improves the efficacy of motor rehabilitative training and alters neuronal density and/or cell proliferation in perilesion cortex following ischemic sensorimotor cortex (SMC) lesions. Adult rats were pre-trained on a skilled reaching task and then received partial unilateral SMC lesions and implantation of electrodes over the remaining SMC. Ten to fourteen days later, rats received daily reach training concurrent with anodal or cathodal 100 Hz CS or no stimulation (NoCS) for 18 days. To label newly generated cells, bromodeoxyuridine (BrdU; 50 mg/kg) was administered every third day of training. Both anodal and cathodal CS robustly enhanced reaching performance compared to NoCS controls. Neuronal density in the perilesion cortex was significantly increased in the cathodal CS group compared to the NoCS group. There were no significant group differences in BrdU-labeled cell density in ipsilesional cortex. Staining with Fluoro-Jade-B indicated that neurons continue to degenerate near the infarct at the time when cortical stimulation and rehabilitation were initiated. These data indicate that epidurally delivered CS greatly improves the efficacy of rehabilitative reach training following SMC damage and raise the possibility that cathodal CS may influence neuronal survival in perilesion cortex.     

Unilateral ischemic sensorimotor cortical damage induces contralesional synaptogenesis and enhances skilled reaching with the ipsilateral forelimb in adult male rats

Unilateral damage to the forelimb representation area of the sensorimotor cortex (SMC) results in a compensatory reliance on the unimpaired (ipsilateral to the lesion) forelimb as well as reorganization of neuronal structure and connectivity in the contralateral motor cortex. Recently, male rats with unilateral electrolytic SMC lesions were found to have enhanced skilled reaching performance with the ipsilesional forelimb compared with sham-operated controls. The present study was performed to determine whether these behavioral findings are replicable using an ischemic lesion and whether there is a link between the enhanced learning and synaptogenesis in motor cortical layer V opposite the trained limb and lesion, as assessed using stereological methods for light and electron microscopy. Rats were given a sham operation or an endothelin-1 (ET-1) induced ischemic SMC lesion. They were then trained for 20 days on a skilled reaching task with the unimpaired limb or received control procedures. As with previous findings using electrolytic lesions, rats with unilateral ischemic SMC lesions performed significantly better using the unimpaired forelimb than did sham-operates. Lesions, but not training, significantly increased the total number of motor cortical layer V synapses per neuron as well as the number of perforated and multisynaptic bouton (MSB) synapses per neuron compared with shams. Thus, in addition to a net increase in synapses, the improved reaching ability was coupled with an increase in synapse subtypes that have previously been linked to enhanced synaptic efficacy. The failure to induce synaptogenesis in layer V with reach training alone is in contrast to previous findings and may be related to training intensity.     

Cortical electrical stimulation combined with rehabilitative training: enhanced functional recovery and dendritic plasticity following focal cortical ischemia in rats

This study assessed the behavioral and dendritic structural effects of combining subdural motor cortical electrical stimulation with motor skills training following unilateral sensorimotor cortex lesions in adult male rats. Rats were pre-operatively trained on a skilled forelimb reaching task, the Montoya staircase test, and then received endothelin-1 induced ischemic lesions of the sensorimotor cortex. Ten to 14 days later, electrodes were implanted over the peri-lesion cortical surface. Rats subsequently began 10 days of rehabilitative training on the reaching task in 1 of 3 conditions: 1. 50 Hz stimulation during training, 2. 250 Hz stimulation during training or 3. no stimulation. No significant difference in performance was found between the 250 Hz and no stimulation groups. The 50 Hz stimulation group had significantly greater rates of improvement with the impaired forelimb in comparison to 250 Hz and no stimulation groups combined. Fifty Hz stimulated animals also had a significant increase in the surface density of dendritic processes immunoreactive for the cytoskeletal protein, microtubule-associated protein 2, in the peri-lesion cortex compared to the other groups. These results support the efficacy of combining rehabilitative training with cortical electrical stimulation to improve functional outcome and cortical neuronal structural plasticity following sensorimotor cortical damage.     

Cortical electrical stimulation combined with rehabilitative training: Enhanced functional recovery and dendritic plasticity following focal cortical ischemia in rats

Abstract

This study assessed the behavioral and dendritic structural effects of combining subdural motor cortical electrical stimulation with motor skills training following unilateral sensorimotor cortex lesions in adult male rats. Rats were pre-operatively trained on a skilled forelimb reaching task, the Montoya staircase test, and then received endothelin-1 induced ischemic lesions of the sensorimotor cortex. Ten to 14 days later, electrodes were implanted over the peri-lesion cortical surface. Rats subsequently began 10 days of rehabilitative training on the reaching task in 1 of 3 conditions: 1. 50 Hz stimulation during training, 2. 250 Hz stimulation during training or 3. no stimulation. No significant difference in performance was found between the 250 Hz and no stimulation groups. The 50 Hz stimulation group had significantly greater rates of improvement with the impaired forelimb in comparison to 250 Hz and no stimulation groups combined. Fifty Hz stimulated animals also had a significant increase in the surface density of dendritic processes immunoreactive for the cytoskeletal protein, microtubule-associated protein 2, in the peri-lesion cortex compared to the other groups. These results support the efficacy of combining rehabilitative training with cortical electrical stimulation to improve functional outcome and cortical neuronal structural plasticity following sensorimotor cortical damage.     

Motor cortical stimulation promotes synaptic plasticity and behavioral improvements following sensorimotor cortex lesions

Cortical stimulation (CS) as a means to modulate regional activity and excitability in cortex is emerging as a promising approach for facilitating rehabilitative interventions after brain damage, including stroke. In this study, we investigated whether CS-induced functional improvements are linked with synaptic plasticity in peri-infarct cortex and vary with the severity of impairments. Adult rats that were proficient in skilled reaching received subtotal unilateral ischemic sensorimotor cortex (SMC) lesions and implantation of chronic epidural electrodes over remaining motor cortex. Based on the initial magnitude of reaching deficits, rats were divided into severely and moderately impaired subgroups. Beginning two weeks post-surgery, rats received 100 Hz cathodal CS at 50% of movement thresholds or no-stimulation control procedures (NoCS) during 18 days of rehabilitative training on a reaching task. Stereological electron microscopy methods were used to quantify axodendritic synapse subtypes in motor cortical layer V underlying the electrode. In moderately, but not severely impaired rats, CS significantly enhanced recovery of reaching success. Sensitive movement analyses revealed that CS partially normalized reaching movements in both impairment subgroups compared to NoCS. Additionally, both CS subgroups had significantly greater density of axodendritic synapses and moderately impaired CS rats had increases in presumed efficacious synapse subtypes (perforated and multiple synapses) in stimulated cortex compared to NoCS. Synaptic density was positively correlated with post-rehabilitation reaching success. In addition to providing further support that CS can promote functional recovery, these findings suggest that CS-induced functional improvements may be mediated by synaptic structural plasticity in stimulated cortex.     

Unilateral ischemic sensorimotor cortical damage in female rats: forelimb behavioral effects and dendritic structural plasticity in the contralateral homotopic cortex

Previous studies in male rats with unilateral sensorimotor cortical (SMC) damage have demonstrated dendritic structural plasticity in the contralateral homotopic cortex and an enhancement of skilled reaching performance in the forelimb ipsilateral to the lesion compared to sham-operated rats. The purpose of this study was to determine if these findings could be replicated in an ischemic lesion model in female rats. Female rats were given sham operations or unilateral ischemic (endothelin-1 induced) damage in the forelimb representation area of the SMC opposite their preferred forelimb. Animals then received either 20 consecutive days of training on a skilled reaching task with the non-preferred/unimpaired forelimb or no-training control procedures. The surface density of dendrites immunoreactive (IR) for microtubule-associated protein 2 (MAP2) was then measured in the motor cortex opposite the trained limb and/or lesion. Female rats with sufficiently large, but not very small, lesions performed better with the unimpaired forelimb than sham-operated rats on the reaching task. The post-lesion reaching performance was not found to be significantly dependent upon estrous stage at the time of surgery, in agreement with previous studies that failed to find sex or sex-hormone effects after other types of SMC damage. Additionally, there were major laminar-dependent increases in the surface density of MAP2 IR dendrites in the cortex opposite lesions and trained limbs. These findings in female rats are consistent with the dendritic and behavioral changes previously found in male rats. They extend these previous findings by indicating that lesion size is an important variable in the enhancement of reaching performance.     

3D重建脑表面中央前回辨识及初级皮层运动功能分布研究

目的研究利用三维重建脑表面成像辨识中央前回的方法及其可靠性。方法难治性癫痫经术前评估需要进行颅内电极植入的病例12例,术前行3T磁共振结构像扫描及运动功能磁共振测试,颅内电极植入后行头颅CT扫描。利用磁共振数据,用Brainvoige软件进行脑表面三维重建,并与硬膜下电极CT融合。根据中央前回的形状走行特点,在重建的脑表面上标记中央前回,进而辨识标记术区中央前回。用皮层电刺激和功能磁共振验证所标记中央前回的可靠性。结果 12例均进行了脑表面三维重建,并标记出了中央前回,硬膜下电极CT电极点与三维脑表面融合。统计中央前回上电极点101个,电刺激运动响应73个,响应率72%;对照组中央前回前1cm（统计中央前沟前2个电极范围）,130个电极,17个电极有运动响应,响应率13%,p值小于0.05;功能磁共振手的运动100%中央前回有激活,中央前回前无明显激活。电刺激及功能核磁均验证了本研究方法确定中央前回准确可靠。结论脑表面成像辨识中央前回准确可行,可以利用各初级运动皮层分布的距离进行详细的初级运动皮层的绘制定位。     

术中直接电刺激在功能区病变手术中的应用（附86例分析）

目的总结术中直接电刺激技术在功能区病变手术中应用的经验。方法对大脑功能区病变手术中应用直接电刺激的86例临床资料进行回顾性总结。本组均在功能区得到保护的前提下,最大程度地切除病灶。结果术中定位出运动区74例。语言相关的功能区37例,感觉区11例。病变全切除51例（59.3％）,次全切除26例（30．2％）,部分切除9例（10．5％）。术后出现短暂性一侧肢体活动障碍23例,短暂语言障碍17例,永久性肢体运动障碍2例。结论皮质电刺激是一种可靠、无创的脑功能区定位方法,正确合理使用该方法有助于提高脑功能区病变的手术质量。