健侧腰骶神经根移位重建脑卒中偏瘫后下肢运动功能的实验研究

Stroke is one of the main diseases threatening human health, most survivors left hemiplegia. The main methods for the treatment of post-stroke hemiplegia is the rehabilitation training, but the result is poor. Previous studies showed that the healthy hemisphere compensatory controlling limb by potential ipsilateral peripheral nerve pathway is an important way for the recovery of limb function after the injury of central nerve system, but the compensation is very limited. So we thought whether we can reconstruct a new neural pathway, to control the paralyzed limb better by the normal brain hemisphere? Our previous study confirmed that severing the L6 nerve root does not damage the healthy limb in rhesus monkeys,L6 (analogous to S1 in humans) nerve root may be used as a donor nerve to repair lumbosacral plexus root avulsion.This study was to further evaluate the effect of severing single normal lumbosacral nerve root on lower extremity motor function, and to evaluate the feasibility and effectiveness of contralateral lumbosacral nerve root transfering to reconstruct the lower limb motor function after hemiplegic stroke in rats. At different time after operation, the behavior, nerve electrophysiological,nerve tracer and muscle tension were used to evaluate the result,small animal brain PET was used to observe the remodeling changes related to the functional areas of the brain after contralateral lumbosacral nerve root transfer.This study provide a theoretical basis for clinical use of contralateral lumbosacral nerve root transfer for reconstruction of the lower limb function of hemiplegia patients after stroke.

脑卒中是当今社会严重危害人类健康的主要疾病之一，存活者中多数遗留有严重的肢体偏瘫。目前治疗脑卒中后偏瘫的主要方法是康复训练，但效果欠佳。以往研究表明健存大脑半球通过潜在的同侧周围神经通路代偿来控制患肢是中枢损伤后肢体功能恢复的重要途径，但这种代偿十分有限。因此我们设想是否可以通过人为建立新的神经通路，使健存的大脑半球更好的控制瘫痪肢体？我们前期研究证实，猕猴腰6神经根切断后对下肢运动功能无明显影响，可作为新的动力源神经。因此本课题拟在进一步评价切断单一腰骶神经根对下肢运动功能影响的基础上，将健侧腰骶神经根移位和患侧腰骶神经根吻合来重建脑卒中偏瘫大鼠的下肢运动功能，并在术后不同时间通过行为学、神经示踪、神经电生理和肌张力检测等方法来评价修复效果，采用小动物脑PET观察健侧腰骶神经根移位后大脑相关功能区的重塑变化，为临床利用健侧腰骶神经根移位治疗脑卒中后偏瘫患者下肢功能障碍提供理论依据。

中枢神经系统损伤后肢体偏瘫是一个尚未解决的医学难题，目前主要的治疗方法是康复训练，但效果欠佳。以往研究表明健存大脑半球通过潜在的同侧周围神经通路代偿来控制患肢是中枢神经损伤后肢体功能恢复的重要途径，但这种代偿十分有限。我们设想是否可以通过人为建立新的神经通路，使健存的大脑半球更好的控制瘫痪肢体？本项目在客观评价切断单一腰骶神经根对下肢运动功能影响的基础上，将健侧腰骶神经根移位和患侧腰骶神经根吻合来重建脑卒中偏瘫大鼠的下肢运动功能，并在术后不同时间通过行为学、神经示踪、神经电生理和肌张力检测等方法来评价修复效果。研究结果发现单一正常腰骶神经根切断后猕猴同侧下肢肌肉功能不会出现明显的变化，可作为新的动力神经修复患侧损伤的神经根；通过静脉注射光敏性化学物质赤藓红，激光定位于支配下肢运动的大脑皮层，损坏一侧神经中枢，可造成对侧下肢痉挛性偏瘫。该方法建立的脑卒中模型稳定，大鼠生存率高，可作为一种建立脑卒中动物模型的有效方法。大鼠脑卒中后一侧肢体出现痉挛性偏瘫，将健侧L4神经根移位至患侧L5神经前根，可显著减轻单侧运动皮层损伤导致的下肢痉挛。临床应用解剖模拟健侧腰骶神经前根移位重建脑卒中后下肢偏瘫，手术操作上具有可行性。上述研究结果表明：通过健侧腰骶神经根移位至患侧，能够显著提高中枢神经损伤后偏瘫肢体的运功功能，该手术方式有望成为治疗中枢神经损伤后肢体偏瘫的一种新方法。本项目的研究结果为临床利用健侧腰骶神经根移位治疗脑卒中后偏瘫患者下肢功能障碍提供了实验和解剖依据。