颈髓电刺激参数对脑血流增加的影响

目的观察颈髓电刺激(SCS)参数和刺激持续时间对脑血流(CBF)的影响。方法以不同波幅、波宽、频率组合的电流刺激大鼠颈髓(C_1/C_2)2 min,同时采用激光多普勒(LDF)记录CBF,得出一个引起LDF值最大化增加的刺激参数(△%LDF)后,再将刺激时间延长至20 min。结果刺激波幅、波宽和频率分别设定为1.5 mA、0.25 ms和50 Hz是SCS升CBF的最佳参数,按以上参数设定后,延长刺激持续时间至20 min,△%LDF在整个刺激时段均保持较高水平。2、5、10及20 min的△%LDF依次为(67.6±2.7)%、(66.2±3.4)%、(61.7±2.4)%和(52.4±2.3)%;前3个时间点△%LDF值的差异无统计学意义(P值均>0.05),最后1个时间点△%LDF值则略有下降(P<0.01),但仍显著高于对照动物(P<0.01)。结论SCS能增加CBF,其效应不随刺激时间延长而消失,SCS有可能成为治疗脑缺血的一种方法。

Effect of cervical spinal cord stimulation parameters on augmentation of cerebral blood flow

Objective Cervical spinal cord stimulation(SCS)has been shown to increase cerebral blood flow(CBF). In the present study,we investigated the effects of various stimulation parameters on CBF augmentation,as well as the tachyphylaxis of the CBF response.Methods SCS was performed 2 min in adult Sprague Dawley rats at C_1-C_2 level with varied stimulation pulse width,frequency and amplitude.CBF was recorded by laser Doppler flowmetry(LDF).When the optimal stimulation parameters that elicited the strongest LDF response was found,we extended the stimulation period up to 20 min.Results SCS elicited a robust increase in cerebral LDF values.The magnitude of the response varied in a dose- dependent manner with the stimulation amplitude.LDF values increased by more than 80% over baseline with an amplitude of 1.5 mA.The optimal pulse width and frequency of the stimulation were 0.25 ms and 50 H_z,respectively.Lengthening the stimulation period to 20 minutes resulted in a persistent increase in cerebral LDF values during the entire stimulation period, although the magnitude of this effect diminished slightly after 15 minutes.Conclusions SCS elicits a robust augmentation in CBF,which lasts the entire stimulation period.Stimulation parameters required for optimal cerebrovascular response are within the normally used therapeutic ranges in the clinical settings.These results provide further evidence that SCS may provide a novel therapeutic strategy for the treatment of cerebral ischemia.(Shanghai Med J,2007,30:520-522)