Lucini Carla, Gatta Claudia
Department of Veterinary Medicine, University of Naples Federico II, 80137 Naples, Italy.
Brain Sci. 2025 Jul 11;15(7):743. doi: 10.3390/brainsci15070743.
Glial cells, once considered mere support for neurons, have emerged as key players in brain function across vertebrates. The historical study of glia dates to the 19th century with the identification of ependymal cells and astrocytes, followed by the discovery of oligodendrocytes and microglia. While neurocentric perspectives overlooked glial functions, recent research highlights their essential roles in neurodevelopment, synapse regulation, brain homeostasis, and neuroimmune responses. In teleost fish, a group comprising over 32,000 species, glial cells exhibit unique properties compared to their mammalian counterparts. Thus, the aim of this review is synthesizing the current literature on fish glial cells, emphasizing their evolutionary significance, diversity, and potential as models for understanding vertebrate neurobiology. Microglia originate from both yolk sac cells and hematopoietic stem cells, forming distinct populations with specialized functions in the adult brain. Neural stem cells, including radial glial cells (RGCs) and neuroepithelial cells, remain active throughout life, supporting continuous neuro- and gliogenesis, a phenomenon far more extensive than in mammals. Ependymocytes line brain ventricles and show structural variability, with some resembling quiescent progenitor cells. Astrocytes are largely absent in most fish species. However, zebrafish exhibit astrocyte-like glial cells which show some structural and functional features in common with mammalian astrocytes. Oligodendrocytes share conserved mechanisms with mammals in myelination and axon insulation.
神经胶质细胞曾被认为仅仅是对神经元起支持作用，如今已成为脊椎动物脑功能的关键参与者。对神经胶质细胞的历史性研究可追溯到19世纪，当时识别出了室管膜细胞和星形胶质细胞，随后又发现了少突胶质细胞和小胶质细胞。尽管以神经元为中心的观点忽视了神经胶质细胞的功能，但最近的研究突出了它们在神经发育、突触调节、脑内稳态和神经免疫反应中的重要作用。硬骨鱼是一个包含超过32000个物种的类群，与哺乳动物的神经胶质细胞相比，硬骨鱼的神经胶质细胞具有独特的特性。因此，本综述的目的是综合当前关于鱼类神经胶质细胞的文献，强调它们的进化意义、多样性以及作为理解脊椎动物神经生物学模型的潜力。小胶质细胞起源于卵黄囊细胞和造血干细胞，在成体脑中形成具有特殊功能的不同群体。神经干细胞，包括放射状胶质细胞（RGCs）和神经上皮细胞，终生保持活跃，支持持续的神经发生和胶质细胞生成，这种现象比在哺乳动物中更为广泛。室管膜细胞排列在脑室中，表现出结构上的变异性，有些类似于静止的祖细胞。大多数鱼类物种中基本不存在星形胶质细胞。然而，斑马鱼表现出类似星形胶质细胞的神经胶质细胞，它们具有一些与哺乳动物星形胶质细胞相同的结构和功能特征。少突胶质细胞在髓鞘形成和轴突绝缘方面与哺乳动物有着保守的机制。
