REGROWTH OF SPINAL CORD AXONS FOLLOWING COLD INJURY

利用一种新开发的模型来产生冰冻 大鼠脊髓损伤的修复与再生 组织的反应将被研究。脑内轴突的再生 这一实验模型提供了扩展我们的 对哺乳动物中枢神经系统再生潜能的认识 创伤或其他损伤后的神经组织。在这些 我们对三个领域的实验特别感兴趣。在 首先，我们将开发更多关于当前模型的信息， 尤其是在细胞的性质和来源方面 基质，生长轴突与基质的关系， 瓦勒带组织的分解及其相互关系 沃勒带中不断生长的轴突。我们将执行这些 首先，研究的是实验形式，即 其特征是细胞基质的最佳发展和 轴突再生。这一损伤将在我们的第一次检查中确定 实验。随后，我们计划探索那些 代表最优的可识别的变化，以便 更彻底地检查轴突、各种胶质细胞的影响 元素、雪旺细胞和间充质成分 轴突重新生长到损伤区域。对这些项目的评估 潜在的变化将通过电子显微镜和 免疫组织化学。其次，我们将进行实验 这将证实光学显微镜的观察结果，即 轴突重新长入损伤处。这些研究将在以下方面进行 最优模型和另一个模型，其中所有相邻的 在冷冻脐带之前，根部将被切断。三、分析了 这些研究的效果将通过使用示踪剂来实现 技巧。体感诱发电位也将 用来在体内评估轴突的状态 在病变内。长达18个月的长期研究将 确定轴突是否可以自发地通过 吞噬细胞清理后的沃勒地带。和 最后，我们计划调查以下吞噬清除 这一地区的。我们将通过以下方法研究损伤的血管反应 静脉注射辣根过氧化物酶通透性的测定 穿过血管壁。通过光学和电子显微镜观察 胶质细胞、轴突、髓鞘、硬膜和软膜的形态变化 将对软膜下组织进行评估。通过免疫组织化学的方法 中可能发生的其他更改 细胞外和细胞外基质。

Utilizing a newly developed model which produces a freezing injury in rat spinal cords, the reparative and regenerative response of the tissue will be studied. The regrowth of axons in this experimental model provides opportunities to extend our understanding of the regenerative potential of mammalian central nervous tissue following traumatic or other injury. In these experiments we are specifically interested in three areas. In the first, we will develop more information about the current model, particularly in terms of the nature and source of the cellular matrix, the relationship of growing axons to the matrix, the breakdown of tissue in the Wallerian zone and the relationships of growing axons in the Wallerian zone. We will perform these studies, at first, upon the experimental form which is characterized by optimal development of the cellular matrix and axonal regrowth. This lesion will be identified in our initial experiments. Subsequently we plan to explore those lesions which represent identifiable variations from the optimal so as to examine more thoroughly the influence of axons, various glial elements, Schwann cells and mesenchymal components upon the regrowth of axons into the injury zone. Evaluation of these potential changes will be by electron microscopy and immunohistochemistry. Secondly, we will perform experiments which will verify the observation, made by light microscopy, that axons regrow into the lesion. These studies will be performed on the optimal model and on another model in which all the adjacent roots will be cut prior to freezing the cord. Analysis of the effects of these studies will be through the use of tracer techniques. Somatosensory evoked potentials will also be employed to permit in vivo evaluation of the status of axons within the lesion. Long range studies up to 18 months will determine whether axons can spontaneously regrow through the Wallerian zone following phagocytic clean-up of the area. And finally, we plan to investigate the following phagocytic clean-up of the area. We will study the vascular response to the lesion by measuring the permeability of intravenous horseradish peroxidase through the vessel walls. By light and electron microscopy the morphologic changes occurring in glia, axons, myelin, pial and subpial tissues will be evaluated. By immunohistochemistry we will attempt to identify other changes that may occur in the cellular and extra-cellular matrix.