Gauthier P, Decherchi P
Laboratoire de Neurobiologie des Fonctions Neurovégétatives, ESA CNRS 6034, Faculté des Sciences et des Techniques de Saint-Jérôme, Marseille. patrick
C R Seances Soc Biol Fil. 1997;191(5-6):695-716.
This review focuses on the regrowth of respiratory pathways after nerve grafting within the central nervous system of the adult rat. After a general presentation of the background and of the grafting procedure, we summarize our nerve grafting results of while it is now well established that severed axons of adult central neurons can regenerate within segments of peripheral nerve partially implanted within the brain or spinal cord, the functional properties of the regenerating neurons remain generally unknown. With a view to assessing the extent to which the functional capacities of central neurons can be maintained after axonal regeneration, we have carried out experiments on central respiratory neurons which are a good example of a highly organized neuronal network with characteristic patterns of spontaneous discharge. We have shown that axonal regrowth of central respiratory neurons was successfully induced in blind-ended medullary and spinal autografts implanted respectively within the respiratory centers of the medulla oblongata and within the cervical spinal cord at the level of descending respiratory pathways. The grafts consisted of true "supplementary nerve" in which normal afferent and efferent respiratory pathways were confirmed by recording respiratory unitary discharges from teased fibers within the grafts. The efferent discharges reflected the activity of central respiratory neurons that had regenerated axons within the grafts: these neurons manifested spontaneous activity and normal responsiveness to respiratory stimuli that resemble those of normal respiratory cells. In order to evaluate the possibility of experimental nerve banking, the feasibility of using short-term and long-term stored nerves as potential spinal nerve grafts was established using in vitro pre-degenerated nerve and cryopreserved nerve grafts after assessment of Schwann cell viability. The extent of respiratory reinnervation of the different grafts (medullary, spinal and stored nerve grafts) was compared. The discussion focuses on the main data and the strategy for future nerve grafting is evoked: functional characteristics of regenerating respiratory axons, extent of graft reinnervation, functional schwann cell survey within stored/grafted nerve and post-traumatic grafting.
本综述聚焦于成年大鼠中枢神经系统内神经移植后呼吸通路的再生。在对背景和移植过程进行总体介绍后，我们总结了神经移植的结果。目前已明确成年中枢神经元的切断轴突可在部分植入脑或脊髓的外周神经节段内再生，但再生神经元的功能特性通常仍不清楚。为了评估轴突再生后中枢神经元的功能能力能在多大程度上得以维持，我们对中枢呼吸神经元进行了实验，中枢呼吸神经元是具有特征性自发放电模式的高度组织化神经元网络的一个很好的例子。我们已经表明，分别植入延髓呼吸中枢和颈脊髓下行呼吸通路水平的盲端延髓和脊髓自体移植中，成功诱导了中枢呼吸神经元的轴突再生。移植体由真正的“补充神经”组成，通过记录移植体内 teased 纤维的呼吸单位放电，证实了正常的传入和传出呼吸通路。传出放电反映了在移植体内再生轴突的中枢呼吸神经元的活动：这些神经元表现出自发活动以及对呼吸刺激的正常反应，类似于正常呼吸细胞。为了评估实验性神经库的可能性，在评估雪旺细胞活力后，利用体外预变性神经和冷冻保存的神经移植物，确定了使用短期和长期储存的神经作为潜在脊髓神经移植物的可行性。比较了不同移植物（延髓、脊髓和储存神经移植物）的呼吸再支配程度。讨论聚焦于主要数据，并引出了未来神经移植的策略：再生呼吸轴突的功能特征、移植物再支配的程度、储存/移植神经内功能性雪旺细胞的研究以及创伤后移植。
