Elmansy Rasha Ahmad, El Shahat Abdal Rahman, Shaikh Masood Ahmed
Department of Anatomy, Faculty of Medicine, Ainshamas University, Egypt.
Neuro Endocrinol Lett. 2010;31(4):530-7.
The present work was aimed at studying the ultra structural changes of the proximal (retinal) stump of the intracranially transected optic nerve of the rat for any possible regenerative ability.
Specimens were collected one (1 wpo) and four weeks(4 wpo) after the transection and the cross sections of the stumps were studied by electron microscopy by dividing them into three zones, (1) the central zone, (2) the intermediate zone, and (3) the peripheral zone.
The present results showed evident morphological changes in these zones both in the 1 wpo and 4 wpo groups. The signs of degeneration were more marked in the central zone than in the peripheral zone and they were more prominent in the 1 wpo group than in the 4 wpo group. The most prominent sign of the degeneration was loss or lack of the healthy myelinated axons. The main evidence of the regenerative ability was the reappearance of the apparently healthy myelinated axonal profiles, with a parallel decrease of the non myelinated ones. This regenerative feature was more prominent peripherally and might be an indication that ischemia was the cause of optic nerve degeneration.
The present work revealed a clear morphological evidence of the regenerative capability of the intracranially transected optic nerve though it is considered as a part of the CNS.
本研究旨在观察大鼠颅内横断视神经近端（视网膜侧）残端的超微结构变化，以探讨其是否具有任何可能的再生能力。
在横断术后1周（1 wpo）和4周（4 wpo）收集标本，将残端横断面分为三个区域，即（1）中央区、（2）中间区和（3）周边区，通过电子显微镜对其进行研究。
本研究结果显示，在1 wpo和4 wpo组的这些区域均出现了明显的形态学变化。中央区的退变迹象比周边区更明显，且在1 wpo组比4 wpo组更突出。退变最显著的迹象是健康有髓轴突的缺失或减少。再生能力的主要证据是明显健康的有髓轴突轮廓重新出现，同时无髓轴突平行减少。这种再生特征在周边区更突出，可能表明缺血是视神经退变的原因。
本研究揭示了颅内横断视神经尽管被认为是中枢神经系统的一部分，但仍具有再生能力的明确形态学证据。
