神经营养素3在面神经的转运状况及对神经细胞的作用研究(英文)

Study on the transport of neurotrophin-3 in facial nerve and its effect on neurons

背景:神经营养素3(Neurotrophin-3,NT-3)是脊椎动物神经系统发育所需要的神经营养因子,促进神经嵴源感觉和交感神经的生存和自然生长。但其效应的发挥需其摄入后经轴突转运至神经元胞体,最终影响细胞的基因表达,产生一系列反应而实现。这种转运在面神经中如何进行,有何特点,尚不十分清楚。目的:利用放射性核素示踪技术研究NT-3在面神经的转运情况,为探讨面神经再生微环境及NT-3对神经细胞的作用提供理论和实验依据。设计:完全随机设计对照实验研究。地点和材料:本研究的地点在四川大学华西医院核医学实验室。材料为神经营养素3。材料为体质量1.8～2.8kg的23只成年健康新西兰兔。干预:将新西兰兔一侧面神经干横切断后置入硅胶再生室,再将131I-NT-3或125I-NT-3或131I-人血清白蛋白(humanserumalbumin,HSA)(10μL/只,约7.4MBq)注入再生室,取注入131I-NT-3或131I-HSA的兔分别在注药后不同时刻行头部冠状位平面显像,取注入125I-NT-3兔的面神经干、脑干和对侧面神经干测定其转运率。另取置入再生室的兔同时在再生室注入1mgNT-3或5.4mgHSA和7.4MBq131I-NT-3后,不同时刻行头部冠状位平面显像。主要观察指标:NT-3在面神经的转运率及状况。结果:注药后4h就有4.05%的125I-NT-3转运到面神经干中,12h为最高峰(27.04%)

BACKGROUND:As a neurotrophic factor, neurotrophin-3(NT-3)is essential for the development of nervous system in amniotes, presented by enhancing survival a nd natural development of sensory and sympathetic nerves derived from nerve ridg e.But these effects required NT-3 transported from axon to neuronal cytoplast a fter uptake and ultimately cellular gene expression,which led to a series of rea ctions.But how and with what kind of property does it transport in facial nerves remained a matter of dispute. OBJECTIVE:Radioactive tracer technique was used to investigate transport chara cter of NT-3 in facial nerves, so as to providing theoretical and experimental basis for exploring microenviorment for facial nerve regeneration and effects of NT-3 on neurons. DESIGN:Completely randomized case-control study. SETTING and MATERIALS:At Nuclear Medicine Laboratory of West China Hospital Af filiated to Sichuan University.NT-3 was used in this study on twenty-three adu lt healthy New Zealand rabbits, weighing 1.8-2.8 kg. INTERVENTIONS:After one lateral facial nerve trunk of adult rabbit was transec ted,a silicone regeneration chamber was inserted between the stumps,131I-NT-3, 125I-NT-3, or 131I-Human serum albumin(HSA)(10 μL/per rabbit,about 7.4 MBq )was administered into the chamber respectively.At the distinct moment of post -injection,the head of rabbit administered with 131I-NT-3,or alternatively 13 1I-HSA was imaged at coronary position; and the bilateral facial nerve trunk an d brain stem of 125I-NT-3 rabbits were collected for determining transport rat e.Meanwhile,after 1mg NT-3 or 5.4 mg HAS or 7.4 MBq 131I-NT-3 was administere d into the chamber of other rabbit,the rabbit was imaged at coronary position of head at different time points. MAIN OUTCOME MEASURES:Transport rate of NT-3 in facial nerves and property. RESULTS:4.05%of 125I-NT-3 was transported into facial nerve trunk at 4 hour s of post-injection,which reached high peak at 12 hours(27.04%);9.85%and 41. 18%of 125I-NT-3 were transported into the brain stem of experimental side at 8 hours and 12 hours respectively.But 131I-HSA transport was not found and the transport of 131I-NT-3 was markedly restrained by NT-3 in facial nerve. CONCLUSION:NT-3 displays a receptor-mediated retrograde transport in facial nerve.