Yang Liu, Chen Dong-feng
Department of Ophthalmology, First Hospital of Peking University, Beijing 100034, China.
Zhonghua Yan Ke Za Zhi. 2006 Feb;42(2):100-3.
To determine whether optic nerve can regenerate after optic nerve crush and weather the regenerating axon reaches the target in the brain in Bcl-2 overexpressing mice.
Left eye optic nerve crush was performed in wild-type (C57Bl/6J) and Bcl-2 transgenic mouse pups at 3 days after birth (P3), followed immediately by the opposite eyeball enucleated. Mouse pups were killed at 4 days post-surgery. Optic nerve regeneration was assessed at the sections of optic nerve and the brain. An anterograde tracer, cholera toxin B subunit conjugated with fluorescein (CTB-F), was applied intraocularly, immediately after optic nerve crush to label retinal ganglion cell axons. Immunofluorescence staining with anti-GAP-43 was carried out to reveal regenerating axons in optic nerve sections.
In wild-type mice, severed optic nerves failed to regenerate. In contrast, in all of the Bcl-2 transgenic mice examined, optic nerves regenerated robustly over long distances, but the regenerating fibers were found to deviate from the optic pathway and grew into the forebrain to form aberrant projection.
When the opposite eyeball is removed in P3 Bcl-2 overexpressing mice with optic nerve was crushed in one side, the guidance from the normal optic pathway is lost, the optic nerve could regenerate and reach the brain, but the regenerating axons could not reach both side of target in the midbrain, they grow into aberrant place of forebrain.
确定在视神经挤压伤后，Bcl-2过表达小鼠的视神经是否能够再生，以及再生轴突能否到达脑内的靶区。
在出生后3天（P3）的野生型（C57Bl/6J）和Bcl-2转基因小鼠幼崽中进行左眼视神经挤压，随后立即摘除对侧眼球。术后4天处死小鼠幼崽。在视神经和脑的切片上评估视神经再生情况。在视神经挤压后立即经眼内注射一种顺行示踪剂，即与荧光素偶联的霍乱毒素B亚基（CTB-F），以标记视网膜神经节细胞轴突。用抗GAP-43进行免疫荧光染色，以显示视神经切片中的再生轴突。
在野生型小鼠中，切断的视神经未能再生。相比之下，在所有检测的Bcl-2转基因小鼠中，视神经能远距离强劲再生，但发现再生纤维偏离视路并长入前脑形成异常投射。
在一侧视神经被挤压的P3 Bcl-2过表达小鼠中，当对侧眼球被摘除后，正常视路的引导丧失，视神经能够再生并到达脑内，但再生轴突不能到达中脑两侧的靶区，而是长入前脑的异常部位。
