Research of morphological, biochemical, biomechanical change of peripheral nerve in aging

1. 将日本大白兔按年龄分为三组；未成熟组（4-6个月）、成熟组（36个月以下）、老年组（36个月以上）。兔坐骨神经因紧张而负荷衰竭。评估了载荷-变形曲线和应力-应变曲线。未成熟组的刚度和抗拉强度均小于成熟组和老龄组。但各组间力学性能无显著差异。在静脉麻醉下手术暴露日本大白兔臂丛。每只兔臂丛向外侧伸展直至电生理传导失败。放置在下树干上的两个标记之间的距离用视频量纲分析系统同时记录下来。结果发现，神经在完全传导阻滞时的应变、负荷和应力分别为8.5%、2.6N、1MPa。采用微腐蚀铸型扫描电镜，采用丙烯塑料注射法（Ohta et al. 1990）对日本猴臂丛微血管结构进行了研究。臂丛肌束外毛细血管少见，而肌束内毛细血管发达，血供密集。臂丛血管分布以节段性血供为主，尤其是锁骨下。

1. Japanese white rabbits were divided into three groups based on their age ; immature groups (4-6 months), mature groups (less than 36 months), aged groups (more than 36 months). The rabbit sciatic nerves were loaded to failure in tension. Load-deformation curves and stress-strain curves were evaluated. The stiffness and tensile strength of imature groups were samller than the mature and aged groups. But there were no significant differences between each groups in mechanical properties.2. The brachial plexus of Japanese white rabbits were surgically exposed under intravenous anesthesia. Each rabbit brachial plexus was stretched laterally up to electrophysiological failure to conduct. The distance between two marks placed on the lower trunks was simultaneously recorded with a video dimensional analysis system. In results, the nerve strain, load and stress at complete conduction block were found to be 8.5%, 2.6N,1MPa, respectively.3. Microvascular architecture of brachial plexus in the Japanese monkey was examined by means of acryl plastic injection method (Ohta et al. 1990) using microcorrosion casts in scanning electron microscope. The extrafascicular capillaries of the brachial plexus were rarely observed, but the intrafascicular capillaries were developped with dense blood supply. Distribution of blood vessels in the brachial plexus was border of segmental blood supply especially under the clavicle.