高频r TMS对健康大鼠认知功能与运动皮质LTP变化的相关性研究

Correlation analysis of cognitive improvement and LTP-like plasticity in healthy rats after rTMS

目的:探究前额叶高频重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)是否能提高健康大鼠认知功能,以及认知功能与运动皮质长时程增强(long-term potentiation,LTP)样可塑性的相关性。方法:24只SD健康成年大鼠,随机分为control组和rTMS组(n=12),rTMS组接受为期4周的高频(10 Hz)r TMS,control组接受4周假刺激。使用水迷宫检测干预前后认知功能的改变;通过TMS结合肌电图运动诱发电位(motor evoked potential,MEP)评价干预前后运动皮质(M1区)LTP样可塑性的改变;通过Western blot检测干预后大鼠M1区NR1、NR2A、NR2B的蛋白表达改变。结果:前额叶高频r TMS可以提高健康大鼠空间情景记忆能力(P<0.05);前额叶高频rTMS可以增强M1区可塑性,表现为M1区LTP样可塑性增高及NR1和NR2A蛋白表达上调(P<0.05);且M1区LTP样可塑性的改变与空间情景记忆能力成正相关(P<0.05)。结论:高频rTMS可改善健康大鼠的空间情景记忆及运动皮质LTP样可塑性,且认知功能与运动皮质LTP样可塑性呈正相关。

Objective:This study aims to investigate the contribution of M1 long-term potentiation(LTP)-like plasticity to the improvement of cognitive function by high frequency repetitive transcranial magnetic stimulation at healthy rat’s head.Methods:A total of 24 rats were randomly divided into control group and rTMS group(n=12).The cognitive function was detected by Morris water maze.The M1 plasticity was reflected by the motor-evoked potential(MEP)before and after rTMS on the primary cortex(M1),the protein expressions of NR1,NR2A and NR2B in the M1 region of rats after high frequency rTMS were detected by Western blot.Results:After treatment,the spatial episodic memory and M1 plasticity showed significant improvement versus the control group(P<0.05).High-frequency rTMS in the prefrontal cortex can enhance the plasticity of the M1 region,which is characterized by increased LTP-like plasticity and up-regulated NR1 and NR2A protein expression in the M1 region.And the changes of LTP-like plasticity in M1region were positively correlated with spatial episodic memory ability(P<0.05).Conclusion:High-frequency rTMS could improve spatial episodic memory and cortical LTP-like plasticity in healthy rats,and the improvement in spatial contextual memory was positively correlated with motor cortical plasticity.