Perry V H, Lund R D
Department of Experimental Psychology, University of Oxford, UK.
J Neurocytol. 1990 Apr;19(2):265-72. doi: 10.1007/BF01217304.
In the majority of mammals axons of retinal ganglion cells are not normally myelinated intraretinally. To test the hypothesis that the lamina cribrosa normally prevents myelin-forming cells from entering the retina we have examined the axons of retinal ganglion cells in conditions where there is no lamina cribrosa. Following transplantation of fetal retinae to the midbrain of newborn rats we have shown that ganglion cell axons within the transplants subsequently become myelinated, providing further evidence that the intraretinal segment of a ganglion cell axon is not refractory to myelination if myelin-forming cells are allowed access. Thus, our results support the hypothesis that the lamina cribrosa normally prevents oligodendrocytes or their precursors from gaining access to the retina. A number of factors may be involved in restricting the migration and differentiation of myelin-forming cells but it is apparent that there is a correlation between the absence or paucity of myelination and the presence of locally increased permeability of the blood-brain barrier. We suggest that proteins derived from plasma may influence oligodendrocyte precursor migration and/or differentiation at these sites.
在大多数哺乳动物中，视网膜神经节细胞的轴突通常不在视网膜内形成髓鞘。为了验证筛板通常会阻止形成髓鞘的细胞进入视网膜这一假说，我们在没有筛板的条件下研究了视网膜神经节细胞的轴突。将胎儿视网膜移植到新生大鼠的中脑后，我们发现移植体内的神经节细胞轴突随后会形成髓鞘，这进一步证明，如果允许形成髓鞘的细胞进入，神经节细胞轴突的视网膜内段并非不能形成髓鞘。因此，我们的结果支持了筛板通常会阻止少突胶质细胞或其前体进入视网膜这一假说。限制形成髓鞘细胞迁移和分化可能涉及多种因素，但显然髓鞘形成缺乏或稀少与血脑屏障局部通透性增加之间存在关联。我们认为，血浆来源的蛋白质可能会影响少突胶质细胞前体在这些部位的迁移和/或分化。
