Vihtelic Thomas S, Soverly Jonathan E, Kassen Sean C, Hyde David R
Center for Zebrafish Research, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
Exp Eye Res. 2006 Apr;82(4):558-75. doi: 10.1016/j.exer.2005.08.015. Epub 2005 Sep 30.
Teleost fish regenerate retinal cells from a population of inner nuclear layer (INL) stem cells. To characterize photoreceptor regeneration in zebrafish (Danio rerio), adult albino fish were subjected to constant intense light to cause photoreceptor cell death. Retinal morphometry was performed on histological sections of control and light-lesioned albino retinas to compare the extent of light damage in the ventral, central and dorsal retinal regions. In addition, opsin immunohistochemistry and TUNEL were used to compare photoreceptor cell death in these different retinal areas, while PCNA immunolabeling quantified the cell proliferation that precedes the photoreceptor regeneration. Transgenic albino; Tg(alpha1-tubulin:egfp) zebrafish were also exposed to the intense light in order to examine regeneration-related gene expression changes. The light-lesioned retinas are characterized by extensive rod and cone photoreceptor cell death in the central and dorsal regions. In contrast, many of the rods and cones survive in the ventral retina. The highest levels of INL cell proliferation, which occurs subsequent to photoreceptor death, correspond to the retinal regions that suffer the greatest levels of photoreceptor damage. In the ventral retina, where photoreceptor cell death is minimal, cell proliferation is confined to the ONL. In addition, EGFP expression from the alpha1-tubulin promoter is increased in Müller glial cells in the light-damaged central and dorsal retina, while transgene expression in the ventral retina is restricted to small, round INL cells. Furthermore, expression of the HuC/D neuronal antigen is detected in a subpopulation of the Müller cells in the light-damaged superior retinal region. These data demonstrate that adult albino zebrafish display retinal regional differences in photoreceptor cell death and in the regeneration-related INL cell proliferation response. The high levels of INL cell proliferation and alpha1-tubulin:egfp transgene expression in the Müller cells may be graded in response to the degree of photoreceptor cell death. This suggests that the levels of photoreceptor damage may directly influence cell responses in the underlying retinal layers.
硬骨鱼能从内核层（INL）干细胞群体中再生视网膜细胞。为了表征斑马鱼（Danio rerio）的光感受器再生情况，成年白化鱼受到持续强光照射以导致光感受器细胞死亡。对对照和光损伤白化视网膜的组织切片进行视网膜形态测量，以比较腹侧、中央和背侧视网膜区域的光损伤程度。此外，视蛋白免疫组织化学和TUNEL用于比较这些不同视网膜区域的光感受器细胞死亡情况，而PCNA免疫标记则对光感受器再生之前的细胞增殖进行定量。转基因白化；Tg(α1 - 微管蛋白:egfp)斑马鱼也暴露于强光下，以检查与再生相关的基因表达变化。光损伤的视网膜特征是中央和背侧区域广泛的视杆和视锥光感受器细胞死亡。相比之下，许多视杆和视锥细胞在腹侧视网膜中存活。光感受器死亡后发生的最高水平的INL细胞增殖，与遭受最大程度光感受器损伤的视网膜区域相对应。在腹侧视网膜中，光感受器细胞死亡极少，细胞增殖局限于外核层（ONL）。此外，α1 - 微管蛋白启动子的EGFP表达在光损伤的中央和背侧视网膜的穆勒胶质细胞中增加，而腹侧视网膜中的转基因表达仅限于小的圆形INL细胞。此外，在光损伤的视网膜上半区域的穆勒细胞亚群中检测到HuC/D神经元抗原的表达。这些数据表明，成年白化斑马鱼在光感受器细胞死亡和与再生相关的INL细胞增殖反应方面表现出视网膜区域差异。穆勒细胞中高水平的INL细胞增殖和α1 - 微管蛋白:egfp转基因表达可能根据光感受器细胞死亡的程度进行分级。这表明光感受器损伤的程度可能直接影响底层视网膜层中的细胞反应。
