Tian Chen, Zou Suqi, Hu Bing
Chinese Academy of Sciences Key Laboratory of Brain Function and Disease and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province, People's Republic of China.
Institute of Life Science, Nanchang University, Nanchang, Jiangxi, People's Republic of China.
Invest Ophthalmol Vis Sci. 2016 Apr 1;57(4):2129-38. doi: 10.1167/iovs.15-17675.
There is no myelination in most mammalian retinas, and if it does happen, it is always accompanied by eye disease. Although lower vertebrates are born with myelin, the precise temporal dynamics of myelination in which oligodendrocytes (OLs) are involved, the origin of OLs, their behaviors in myelination, and their function in retinas have not yet been clearly elaborated. Therefore, we focus on these aspects to study the oligodendrocytes and myelin sheath in the zebrafish retina.
Retinal whole mount, immunohistochemistry, and optic nerve retrograde labeling were performed to monitor the myelination. Taking advantage of whole eye eversion and transplantation techniques, we studied the retinal origin of OLs. By optic nerve transplantation, we can observe single OLs in zebrafish retina. The optokinetic reflex (OKR) behavior test and the lysophosphatidylcholine (LPC)-induced retinal demyelination model were used to test the function of the myelin.
First, we demonstrated that myelination starts at 28 dpf in zebrafish retinas. Second, we directly proved that all the OLs in zebrafish retinas migrated from the optic nerve rather than from a domestic source. Third, we found that compared with adult OLs, younger OLs tend to generate longer but a fewer number of internodes. Finally, we found that the myelin in zebrafish eyes is functionally relevant to the elegant OKR.
Our data suggest that the extraocular source of OLs first appeared at 28 dpf in zebrafish retina and then gradually developed with age, which contribute to optokinetic responses.
大多数哺乳动物的视网膜中不存在髓鞘形成，即便出现髓鞘形成，也总是伴随着眼部疾病。尽管低等脊椎动物出生时就有髓鞘，但少突胶质细胞（OLs）参与的髓鞘形成的确切时间动态、OLs的起源、它们在髓鞘形成中的行为以及它们在视网膜中的功能尚未得到明确阐述。因此，我们聚焦于这些方面来研究斑马鱼视网膜中的少突胶质细胞和髓鞘。
进行视网膜整装、免疫组织化学和视神经逆行标记以监测髓鞘形成。利用全眼球翻转和移植技术，我们研究了OLs的视网膜起源。通过视神经移植，我们可以观察斑马鱼视网膜中的单个OLs。使用视动反射（OKR）行为测试和溶血磷脂酰胆碱（LPC）诱导的视网膜脱髓鞘模型来测试髓鞘的功能。
首先，我们证明斑马鱼视网膜中的髓鞘形成始于28日龄。其次，我们直接证明斑马鱼视网膜中的所有OLs均从视神经迁移而来，而非源自本地。第三，我们发现与成年OLs相比，较年轻的OLs倾向于产生更长但数量更少的节间。最后，我们发现斑马鱼眼中的髓鞘在功能上与优雅的OKR相关。
我们的数据表明，OLs的眼外来源首先出现在斑马鱼视网膜的28日龄，然后随着年龄的增长逐渐发育，这有助于视动反应。
