CELLULAR MECHANISMS FOR NERVE REPAIR

神经修复的细胞机制

基本信息

批准号：
6539955
负责人：
Kenneth J Muller
金额：
$ 26.08万
依托单位：
UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-07-18 至 2005-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6539955
关键词：
Hirudinea axon cell migration electric field immunocytochemistry in situ hybridization laminin microglia migration inhibition factor nerve injury nervous system regeneration neuronal guidance nitric oxide nitric oxide synthase video microscopy

项目摘要

DESCRIPTION (Verbatim from Applicant's Abstract): A major problem in neurobiology concerns the mechanisms by which damaged neurons may re-grow axons and form selective connections to restore function. We propose to test the role of migrating microglia in successful axonal regeneration that follows injury to the leech nervous system. Migration of microglia occurs promptly, accounts for the increase in cell numbers at the lesion, and appears influenced by nitric oxide synthase activity, which is rapidly up regulated at the lesion. Microglial migration is also affected by applied electric fields of a size consistent with injury currents we measure at the lesion. Evidently microglia deposit laminin, a component of the extracellular matrix that promotes axon growth. The leech is particularly advantageous for these studies because (1) its ganglia contain identifiable neurons capable of regenerating specific connections following axotomy, (2) individual microglia can be tracked and their movements charted minute by minute, and (3) adult and embryonic nervous systems can be manipulated and examined both in vivo and in vitro. Experiments that interfere with and block accumulation of microglia at injury sites will test the role of microglia in sprouting and regeneration. Immunocytochemistry has shown abundant laminin transiently in the embryonic leech nervous system along axon pathways. Following injury to the adult nervous system, laminin reappears (first in patches at the lesion, later in streaks) in advance of axons. Whether the microglia that migrate toward the site of the lesion produce the laminin, as in vitro, will be determined using antibodies and in situ hybridization with our riboprobes for laminin. We will determine whether the streaks of laminin, which may guide regenerating axons, mark the paths of migrating microglial cells; fluorescently labeled microglia will be tracked in living preparations using low-light video microscopy. Alterations of nitric oxide levels and its synthesis and of electric fields such as those generated by the lesion will determine the actions of nitric oxide and fields in regulating microglial migration. These studies will clarify the roles of microglia and of laminin in axonal regeneration following injury, and may suggest strategies for achieving equally successful axonal repair in the mammalian nervous system.

描述（逐字病来自申请人的摘要）：神经生物学涉及受损神经元可能重长轴突的机制并形成选择性连接以还原功能。我们建议测试角色在成功的轴突再生中迁移的小胶质细胞的损伤水ech神经系统。小胶质细胞的迁移迅速发生，帐户病变处的细胞数量增加，并且似乎受一氮影响氧化物合酶活性在病变处迅速调节。小胶质细胞迁移也受到大小的施加电场的影响与损伤电流一致，我们在病变处测量。显然是小胶质细胞沉积层粘连蛋白，这是促进轴突的细胞外基质的成分生长。水ech对于这些研究特别有利，因为（1）它的神经节包含能够再生特定的可识别神经元轴切开后的连接，（2）可以跟踪单个小胶质细胞，并且他们的动作划分了一分钟，（3）成人和胚胎神经系统可以在体内和体外进行操纵和检查。实验这种干扰和阻塞小胶质细胞在受伤部位的积累将测试小胶质细胞在发芽和再生中的作用。免疫细胞化学已经在胚胎水ech神经系统中瞬时显示出丰富的层粘连蛋白沿轴突路径。受伤后的成人神经系统，粘膜层蛋白重新出现（首先是病变的斑块，后来在条纹上）轴突。迁移到病变部位的小胶质细胞是否会产生层粘连蛋白在体外，将使用抗体和原位确定与层粘连蛋白的核糖探针杂交。我们将确定是否层粘连蛋白的条纹，可能引导轴突再生，标记迁移小胶质细胞；荧光标记的小胶质细胞将在使用弱光视频显微镜的生活制备。硝酸的改变氧化物水平及其合成和电场，例如产生的电场通过病变将确定一氧化氮和田间的作用调节小胶质细胞迁移。这些研究将阐明受伤后轴突再生中的小胶质细胞和层粘连蛋白，可能提出实现同样成功的轴突修复的策略哺乳动物神经系统。