Department of Neurology, the First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi Zhuang Autonomous Region 530021, China.
Department of Neurology, Wuzhou Red Cross Hospital, Wuzhou, Guangxi Zhuang Autonomous Region 543002, China.
J Stroke Cerebrovasc Dis. 2020 Dec;29(12):105235. doi: 10.1016/j.jstrokecerebrovasdis.2020.105235. Epub 2020 Sep 15.
In this study, we investigated the spontaneous neural plasticity on the contralateral side in hypertensive rats, including the expression of nerve growth factors (synaptophysin [SYN] and growth-associated protein 43 [GAP-43]), and the association between nerve fiber sprouting and redistribution, and the recovery of motor functions following sensorimotor cortical infarction.
Initially, Sprague-Dawley rats were induced with renal hypertension by the bilateral renal arteries clips method. Further, they were induced with cerebral ischemia by the middle cerebral artery electrocoagulation method; 70 male rats completed the study. We compared the changes in the corticospinal tract (CST) and the expressions of SYN and GAP-43 on the contralateral side in rats with cerebral infarction using immunohistochemical staining, western blot, and biotinylated dextran amine (BDA) tracing analyses. The recovery of motor function in rats after cortical infarction was evaluated by the foot-fault and beam-walk tests.
The motor behavior tests revealed that the motor function of rats could recover to various degrees after focal cortical infarction. Compared with the sham-operated group, the SYN and GAP-43 levels increased in the motor cortex of the opposite hemisphere within 28 days after middle cerebral artery occlusion (MCAO). The increase in SYN and GAP-43 expressions presented differently in layers Ⅱ, Ⅲ, and Ⅴ. The amount of BDA-positive fibers also increased significantly in the denervated cervical spinal gray matter on day 56 post-MCAO.
The increases in SYN and GAP-43 on the contralateral side of the motor cortex could promote CST sprouting and rewiring in the spinal cord gray matter and also spontaneous motor function recovery after cortical infarction.
本研究旨在探讨高血压大鼠对侧自发性神经可塑性，包括神经生长因子（突触素 [SYN] 和生长相关蛋白 43 [GAP-43]）的表达，以及神经纤维发芽和重新分布与大脑感觉运动皮层梗死后运动功能恢复之间的关系。
首先，通过双侧肾动脉夹闭法诱导 Sprague-Dawley 大鼠产生高血压，然后通过大脑中动脉电凝法诱导其发生大脑缺血；70 只雄性大鼠完成了本研究。我们通过免疫组织化学染色、Western blot 和生物素化葡聚糖胺（BDA）示踪分析比较了大脑梗死大鼠对侧皮质脊髓束（CST）和 SYN、GAP-43 表达的变化。采用足失误和束走试验评估大鼠大脑皮层梗死后的运动功能恢复情况。
运动行为学测试表明，大脑皮层局灶性梗死后大鼠的运动功能可在不同程度上得到恢复。与假手术组相比，大脑中动脉闭塞（MCAO）后 28 天，对侧运动皮层的 SYN 和 GAP-43 水平升高。SYN 和 GAP-43 的表达增加在皮层Ⅱ、Ⅲ和Ⅴ层呈现不同的变化模式。MCAO 后 56 天，失神经支配的颈段脊髓灰质中 BDA 阳性纤维数量也显著增加。
运动皮层对侧 SYN 和 GAP-43 的增加可促进 CST 在脊髓灰质中的发芽和重新布线，也可促进大脑皮层梗死后自发性运动功能恢复。
