Dog sciatic nerve gap repaired by artificial tissue nerve graft

The feasibility of repairing dog sciatic nerve damage by using a biodegradable artificial tissue nerve graft enriched with neuroregenerating factors is investigated. The artificial nerve graft was implanted to a 30 mm gap of the sciatic nerve damage in 7 dogs. The dogs with the same nerve damage that were repaired by interposition of the autologous nerve or were given no treatment served as control group 1 or 2, respectively. The observations include gross and morphological observations, immune reaction, electrophysiological examination, fluorescence tracing of the neuron formation and the number of the neurons at the experimental sites, etc. Results showed that 6 months after the implantation of the graft, the regenerated nerve repaired the damage of the sciatic nerve without occurrence of rejection and obvious inflammatory reaction in all 7 dogs, and the function of the sciatic nerve recovered with the nerve conduction velocity of (23.91±11.35)m/s. The regenerated neurons and the forming of axon could be observed under an electron microscope. This proves that artificial tissue nerve graft transplantation can bridge the damaged nerve ends and promote the nerve regeneration.     

神经生长因子

概述了神经生长因子的分子结构及作用机制，综述了神经生长因子的生理功能，神经生长因子不仅对神经细胞的存活，生长发育，分化，再生和功能维持起调控作用。同时也能诱导细胞凋亡。     

bFGF对自体神经移植后神经再生和神经元相关性的影响

目的 探讨bFGF对自体神经移植后神经再生和神经元相关性的影响.方法 切断大白鼠右侧坐骨神经10mm,在原位作神经外膜缝合,实验组注射bFGF 100u/d,共10d,对照组注射生理盐水10d,术后12周取材.光镜观察,并计数再生神经纤维和神经元的绝对值,得出恢复率以及用统计学方法得出它们的相关性.结果 两组均可见再生神经纤维通过吻合口,并向远端延伸.两组神经再生率与脊髓前角运动细胞或者脊神经节细胞存活率的相关系数均非常接近1,但实验组和对照组的组间相关系数无显著性差异.结论 周围神经再生率与相应的脊髓前角运动细胞或者脊神经节细胞存活率之间的正相关关系是固有的,不会随bFGF的使用而改变     

bFGF对自体神经移植后神经再生和神经元相关性的影响

目的探讨bFGF对自体神经移植后神经再生和神经元相关性的影响。方法切断大白鼠右侧坐骨神经10mm,在原位作神经外膜缝合,实验组注射bFGF100u/d,共10d,对照组注射生理盐水10d,术后12周取材。光镜观察,并计数再生神经纤维和神经元的绝对值,得出恢复率以及用统计学方法得出它们的相关性。结果两组均可见再生神经纤维通过吻合口,并向远端延伸。两组神经再生率与脊髓前角运动细胞或者脊神经节细胞存活率的相关系数均非常接近1,但实验组和对照组的组间相关系数无显著性差异。结论周围神经再生率与相应的脊髓前角运动细胞或者脊神经节细胞存活率之间的正相关关系是固有的,不会随bFGF的使用而改变     

Relationship between the nerve action potential and transmitter release from sympathetic postganglionic nerve terminals

At the skeletal neuromuscular junction, electrophysiological methods have provided much useful information about the mechanisms involved in the release of transmitter. At the autonomic neuroeffector junction it has not been possible to carry out similar studies. Here we report a method of extracellular recording which allows simultaneous measurement of both the nerve action potential and transmitter release from postganglionic sympathetic nerve terminals. We have confirmed that release is intermittent, but the importance of this new approach is that the relationship between the nerve terminal action potential and transmitter release can be studied unambiguously for the first time. Thus we are able to show unequivocally that intermittence is caused by a low probability of release in the invaded varicosity and not by failure of the action potential to invade the varicosity.     

Interleukin-1 regulates synthesis of nerve growth factor in non-neuronal cells of rat sciatic nerve

The Schwann cells and fibroblast-like cells of the intact sciatic nerve of adult rats synthesize very little nerve growth factor (NGF). After lesion, however, there is a dramatic increase in the amounts of both NGF-mRNA and NGF protein synthesized by the sciatic non-neuronal cells. This local increase in NGF synthesis partially replaces the interrupted NGF supply from the periphery to the NGF-responsive sensory and sympathetic neurons, whose axons run within the sciatic nerve. Macrophages, known to invade the site of nerve lesion during wallerian degeneration, are important in the regulation of NGF synthesis. Here we demonstrate that the effect of macrophages on NGF-mRNA levels in cultured explants of sciatic nerve can be mimicked by conditioned media of activated macrophages, and that interleukin-1 is the responsible agent.