Departamento de Bioloxía Funcional, CIBUS, Facultade de Bioloxía, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Departamento de Zooloxía, Xenética y Antropoloxía Física, Facultade de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, Spain.
Int J Mol Sci. 2021 Oct 28;22(21):11715. doi: 10.3390/ijms222111715.
It is largely assumed that the teleost retina shows continuous and active proliferative and neurogenic activity throughout life. However, when delving into the teleost literature, one finds that assumptions about a highly active and continuous proliferation in the adult retina are based on studies in which proliferation was not quantified in a comparative way at the different life stages or was mainly studied in juveniles/young adults. Here, we performed a systematic and comparative study of the constitutive proliferative activity of the retina from early developing (2 days post-fertilisation) to aged (up to 3-4 years post-fertilisation) zebrafish. The mitotic activity and cell cycle progression were analysed by using immunofluorescence against pH3 and PCNA, respectively. We observed a decline in the cell proliferation in the retina with ageing despite the occurrence of a wave of secondary proliferation during sexual maturation. During this wave of secondary proliferation, the distribution of proliferating and mitotic cells changes from the inner to the outer nuclear layer in the central retina. Importantly, in aged zebrafish, there is a virtual disappearance of mitotic activity. Our results showing a decline in the proliferative activity of the zebrafish retina with ageing are of crucial importance since it is generally assumed that the fish retina has continuous proliferative activity throughout life.
人们普遍认为，硬骨鱼的视网膜在其整个生命周期中都具有持续的活跃增殖和神经发生活性。然而，当深入研究硬骨鱼的文献时，人们发现关于成年视网膜具有高度活跃和持续增殖的假设是基于这样的研究：这些研究没有以比较的方式在不同的生命阶段量化增殖，或者主要在幼鱼/年轻成年鱼中进行研究。在这里，我们对从早期发育（受精后 2 天）到老年（受精后 3-4 年）的斑马鱼的视网膜的组成性增殖活性进行了系统的比较研究。通过对 pH3 和 PCNA 进行免疫荧光染色，分别分析有丝分裂活性和细胞周期进程。我们观察到，尽管在性成熟期间发生了次级增殖波，但随着年龄的增长，视网膜的细胞增殖会下降。在这个次级增殖波期间，增殖和有丝分裂细胞的分布从中央视网膜的内层到外层核层发生变化。重要的是，在老年斑马鱼中，有丝分裂活性几乎消失。我们的研究结果表明，随着年龄的增长，斑马鱼视网膜的增殖活性下降，这一点至关重要，因为人们普遍认为鱼类视网膜在整个生命周期中都具有持续的增殖活性。
