AGE-RELATED INFLUENCES ON MUSCLE AND NERVE REGENERATION

骨骼肌和周围神经的再生在老年人比老年人差。 在年轻的老鼠。 根据异龄嫁接获得的数据， 模型中，与年龄相关的主机变化似乎会损害容量 肌肉和神经的再生。 本方案的具体目标 项目是测试四个群体假设，在旧的相比， 幼鼠A.肌肉移植物再生不良与缺乏 神经再支配; B.在肌肉中不存在结构或功能差异 纤维在早期prenervedition阶段，但结构和功能 的肌肉纤维和运动单位受损， 阶段; C.受损的轴突再生与神经元的缺陷有关。 基因表达、髓鞘清除、巨噬细胞和雪旺细胞 功能; D.跨年龄段的神经移植物最终变得适应于 宿主的特性。 假设A和B将由以下人员进行检验： 单个肌纤维、运动单位和整体的生理分析 肌肉特性、组织化学和神经染色以及电子 显微镜 假设C和D将通过免疫细胞化学进行测试， 原位杂交，形态分析，放射自显影，生长 因子分析和北方和西方印迹。 的意义 拟议的研究是澄清负责的机制， 用于改善老年动物的肌肉和神经再生。 的 这项研究的长期目标是为改善 修复老年人受损的肌肉和神经。

Skeletal muscle and peripheral nerve regenerate more poorly in old than in young rats. On the basis of data obtained from cross-age grafting models, an age-related change in the host appears to impair the capacity of muscle and nerve to regenerate. The Specific Aims of this Program Project are to test four Group Hypotheses that in old as compared with young rats: A. poor regeneration of muscle grafts is related to deficient reinnervation; B. no structural or functional differences exist in muscle fibers during an early preinnervation stage, but structure and function of muscle fibers and motor units are impaired during a postinnervation stage; C. impaired axonal regeneration is related to defects in neuronal gene expression, myelin clearance, and macrophage and Schwann cell function; and D. cross-age nerve grafts ultimately become adapted to characteristics of the host. Hypotheses A and B will be tested by physiological analysis of single muscle fiber, motor unit and whole muscle properties, histochemistry and nerve staining, and electron microscopy. Hypotheses C and D will be tested by immunocytochemistry, in situ hybridization, morphometric analysis, autoradiography, growth factor analysis and Northern and Western blotting. The significance of the proposed research is the clarification of the mechanisms responsible for the improvement of muscle and nerve regeneration in old animals. The long-term goal of this research is to provide the basis for improving the repair of damaged muscle and nerve in old individuals.