Effect of Median Nerve Electrical Stimulation on Synaptic Plasticity in Ischemic Stroke Rats
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摘要:
目的 探究正中神经电刺激对缺血性脑卒中大鼠突触可塑性的影响及其初步的作用机制。 方法 18只SD健康雄性大鼠随机分为假手术组(Sham组,n = 6)、缺血性脑卒中组(MCAO组,n = 6)、正中神经电刺激组(MNES组,n = 6),采用线栓法建立大鼠左侧大脑中动脉闭塞模型,假手术组不插入线栓,正中神经电刺激组在造模后第3天给予正中神经电刺激干预,隔天干预,干预 7次后进行行为学检测、HE染色检测正中神经的损伤情况、尼式染色检测脑梗死体积、Western blot检测与突触可塑性相关蛋白的表达水平以及电镜检测。 结果 HE染色显示正中神经电刺激对脑卒中大鼠的正中神经未造成损伤,正中神经被膜结果完整,无明显炎细胞浸润。与MCAO组相比,MNES组大鼠的神经功能以及损伤侧前肢的运动功能和协调能力显著改善(P < 0.01)。与MCAO组相比,MNES组大鼠脑梗死体积明显减小(P < 0.05),缺血半影区尼氏小体的核固缩现象减少。与MCAO组相比,正中神经电刺激干预后,MNES组大鼠皮层中与突触可塑性相关蛋白PSD95、synI的表达水平明显上调(P < 0.05),缺血损伤侧皮层的突触数量显著增多(P < 0.01)。 结论 正中神经电刺激是改善脑卒中后受损神经功能安全有效的治疗措施,其作用机制与促进突触可塑性有关。 Abstract:Objective To investigate the effects and mechanisms of median nerve electrical stimulation on synaptic plasticity in ischemic stroke rats. Methods 18 healthy male SD rats were randomly divided into Sham group(n = 6), ischemic stroke group(MCAO group, n = 6) and median nerve electrical stimulation group(MNES group, n = 6). The left middle cerebral artery occlusion model of rats was established by thread plug method. Thread plug was not inserted in sham group. The median nerve electrical stimulation group was given median nerve electrical stimulation intervention on the 3rd day after modeling, and intervention on the next day. After intervention for 7 times, behavioral detection, HE staining was used to detect median nerve injury. Nissl staining was used to detect cerebral infarction volume. Western blot was used for detection of the expression level of proteins related to synaptic plasticity, and electron microscopy was performed. Results HE staining showed that median nerve electrical stimulation did not cause damage to the median nerve in stroke rats, and the median nerve membrane was intact without obvious inflammatory cells. Compared with MCAO group, the neural function, motor function and coordination of the injured forelimb in MNES group were significantly improved(P < 0.01). Compared with MCAO group, cerebral infarction volume in MNES group was significantly reduced(P < 0.05), the pyknosis of Nissl bodies in ischemic penumbra decreased. Compared with MCAO group, the expression levels of synaptic plastication-related proteins PSD95 and synI in the cortex of MNES group were significantly up-regulated after median nerve electrical stimulation(P < 0.05), the number of synapses in the ischemic cortex increased significantly(P < 0.01). Conclusion Median nerve electrical stimulation is a safe and effective therapeutic measure to improve nerve function after stroke, and its mechanism is related to promoting synaptic plasticity. -
表 1 神经功能缺损评分
Table 1. Neurological severity score
评分 神经功能缺损评估 0分 无神经损伤 1分 提尾时对侧前肢持续弯曲而无其他异常 2分 将大鼠置于软塑封垫上,轻推其肩膀数次,出现抵抗力下降 3分 在地面上活动时向上拉其尾,向瘫痪侧旋转 4分 自行行走时即向瘫痪侧旋转 5分 不能自行行走 6分 无自发活动 7分 死亡 表 2 踏错实验评分
Table 2. Foot-fault test scores
评分 运动表现 0分 完全踩空,身体失去平衡和正常的姿势 1分 脚搭在横梯上,但当该脚承重时下滑并掉落,影响行走 2分 脚搭在横梯上,当该脚承重时滑下,但并未掉落,也不影响行走和平衡 3分 脚掌置于横梯上,但在该脚承重前动物将该脚迅速抬起并移到另一横梯上 4分 脚想放到一横梯上,但因没有接触到而放在了另一横梯上 5分 脚部分置于横梯上,行走时由脚踝、脚趾或膝盖承重 6分 脚掌置于正中,并能完全承重 -
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