大鼠坐骨神经切断后足底皮肤血流灌注变化研究

Time-lapse LDPI analysis of skin territory following sciatic nerve transection in rats

目的:了解周围神经损伤后患区皮肤血流灌注的动态变化及其与神经传导功能和轴突溃变状况之间的关系。方法:建立大鼠坐骨神经切断模型,应用激光多普勒血流灌注成像动态分析足底血流变化,分别采用腓肠肌复合肌动作电位(CMAP)检测和免疫组织化学染色分析损伤远侧神经传导功能变化和轴突溃变情况。结果:坐骨神经切断后相应足底皮肤血流灌注急剧增高,高灌注状态在损伤后3 d内恢复到接近正常;神经切断后24 h刺激损伤远侧段神经记录的腓肠肌CMAP波幅减小95%以上;损伤后4 d远侧神经段内绝大部分轴突已溃变清除。结论:大鼠神经切断后患区皮肤血流呈高灌注状态且在损伤后3 d内逐渐恢复到正常水平,这种高灌注状态可能不依赖于远侧段神经冲动传导功能的保持,但与轴突溃变状态相关。

Objective：This study was performed to figure out how dermal blood flow changed in skin territory following peripheral nerve injury,and to determine whether this change correlated to alteration of excitability/conductivity or axonal degeneration of the nerve distal to injury.Methods：Skin blood flow was monitored by time-lapse laser Doppler perfusion imaging（LDPI） in a rat model of sciatic nerve transection injury.Meanwhile,compound muscle action potentials（CMAPs） were recorded in gastrocnemius muscle by applying electrical stimuli to the nerve distal to injury,and the distal nerve was immunostained for neurofilament-200 and S-100 protein.Results：Sciatic nerve transection led to an immediate and robust increase of blood perfusion,which recovered to normal extent in 3 days post-injury,in the ipsilateral hind paw.In 24 h after injury,CMAP amplitude reduced more than 95% in gastrocnemius muscle upon stimulating the nerve distal to injury.However,the majority of axons were seen to degenerate in the distal nerve aftre 4 days.Conclusion：Blood perfusion increase in skin territory,resulted from the sciatic nerve transection,was gradually recovered to normal in 3 days post-injury.Although there seemed a correlation between dermal perfusion increase and axonal degeneration,the maintenance of axonal excitability in the distal nerve did not necessarily correlate to increase of skin blood perfusion.