Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain.
Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca (IMIB-Arrixaca), Murcia, Spain.
Exp Eye Res. 2018 Sep;174:93-97. doi: 10.1016/j.exer.2018.05.029. Epub 2018 May 29.
In this study we have compared the response to optic nerve crush (ONC) and to optic nerve transection (ONT) of the general population of retinal ganglion cells in charge of the image-forming visual functions that express Brn3a (Brn3aRGCs) with that of the sub-population of non-image forming RGCs that express melanopsin (mRGCs). Intact animals were used as control. ONT and ONC were performed at 0.5 mm from the optic disk, and retinas dissected 3, 5, 7, 14, 30, 45 or 90 days later (n = 5/injury/time point). In all the retinas, Brn3aRGCs and mRGCs were identified and their survival analyzed quantitatively and topographically. There were no differences in the course of RGC loss between lesions. The decrease of RGCs was significant at short time points (3 or 5 days for Brn3a or m RGCs, respectively) and, up to 14 days, the course of loss of both RGC populations was similar, surviving at this time point between 20 and 22% of their original population. However, while the loss of Brn3aRGCs continues steadily up to 90 days when only 5-6% of them still remain, the loss of mRGCs stops at 14 days, and the proportion of surviving mRGCs remains constant up to 90 days (26-30%). In conclusion, mRGC do not respond to axotomy in the same way than the rest of RGCs, and so whilst image-forming RGCs die in two exponential phases a quick one and a slow protracted one, non-image forming RGCs die only during the first quick phase.
在这项研究中，我们比较了视神经挤压（ONC）和视神经横断（ONT）对表达 Brn3a（Brn3aRGCs）的负责成像视觉功能的视网膜神经节细胞（RGC）的总体反应，以及表达黑视蛋白（mRGCs）的非成像 RGC 的亚群反应。完整的动物作为对照。ONT 和 ONC 在距视盘 0.5 mm 处进行，然后在 3、5、7、14、30、45 或 90 天后解剖视网膜（n = 5/损伤/时间点）。在所有视网膜中，鉴定了 Brn3aRGCs 和 mRGCs，并定量和地形学分析了它们的存活情况。两种病变中 RGC 丧失的过程没有差异。RGC 的减少在短时间点（分别为 Brn3a 或 m RGCs 的 3 或 5 天）时显著，并且在 14 天之前，两种 RGC 群体的丧失过程相似，此时存活的 RGC 数量为其原始数量的 20-22%。然而，虽然 Brn3aRGC 的丧失持续到 90 天，此时只剩下 5-6%，但 mRGC 的丧失在 14 天停止，存活的 mRGC 比例在 90 天内保持不变（26-30%）。总之，mRGC 对轴突切断的反应与其他 RGC 不同，因此，虽然形成图像的 RGC 以两个指数相死亡——快速相和缓慢延长相，而非形成图像的 RGC 仅在第一个快速相死亡。
