Maki Hideki, Watanabe Masami, Tokita Yoshihito, Saito Kiyoshi, Yoshida Jun
Department of Neurosurgery, Nagoya University School of Medicine, Nagoya, Aichi, Japan.
J Neurosci Res. 2003 Apr 15;72(2):218-26. doi: 10.1002/jnr.10562.
We reported previously that alpha ganglion cells in the cat retina have the highest ability in axonal regeneration. To examine whether alpha cells regenerate axons faster, we estimated the rate of axonal regeneration of retinal ganglion cells (RGCs) with transplantation of a peripheral nerve (PN) segment. After 4, 6, and 8 weeks of survival, regenerated RGCs were double-labeled with two fluorescent dyes injected separately at 10 mm and 20 mm from the connected site. From a scatter diagram of double-labeling ratios, we estimated that axons reached 20 mm by 3.2 weeks. Immunostaining suggested that first axon sprouts entered a PN segment on Day 4. These values enabled us to estimate average rates of axonal regeneration as 1.1 mm/day for all the RGCs. Proportions of cell types of regenerated RGCs were obtained with Lucifer yellow injections, and those of alpha cells were higher than those in normal retinas in any periods. From analysis of scatter diagrams, we estimated axonal growth rate of alpha, beta, and non-alpha/beta cells as 1.4, 1.1, 1.0 mm/day, respectively. The higher regeneration rate of alpha cells may reflect greater regenerative ability compared to other cell types. The present system also provides control values when a method to promote axonal regeneration is developed.
我们之前报道过，猫视网膜中的α神经节细胞具有最高的轴突再生能力。为了研究α细胞的轴突再生速度是否更快，我们通过移植外周神经（PN）段来估计视网膜神经节细胞（RGCs）的轴突再生速度。在存活4、6和8周后，分别在距连接部位10毫米和20毫米处注射两种荧光染料对再生的RGCs进行双重标记。从双重标记比率的散点图中，我们估计轴突在3.2周时到达20毫米处。免疫染色表明，第4天第一批轴突芽进入PN段。这些数值使我们能够估计所有RGCs的轴突再生平均速度为1.1毫米/天。通过注射路西法黄获得再生RGCs的细胞类型比例，在任何时期α细胞的比例都高于正常视网膜中的比例。通过对散点图的分析，我们估计α、β和非α/β细胞的轴突生长速度分别为1.4、1.1、1.0毫米/天。与其他细胞类型相比，α细胞较高的再生速度可能反映了其更强的再生能力。当开发出促进轴突再生的方法时，本系统也能提供对照值。
