Gliogenesis in the Male Japanese Quail (Coturnix japonica) Brain

Abstract

Gliogenesis is a process that involves the generation of new glial cells (astrocytes, oligodendrocytes, and microglia) from neural stem cells (NSCs) or neural progenitor cells (NPCs) in both developing and adult individuals. The process of gliogenesis is essential for the preservation of the functional integrities of the central nervous system (CNS) from development to adulthood. The present thesis aimed to study gliogenesis and neurogenesis in the male Japanese quail (Coturnix japonica) brain at three different developmental stages: juvenile, subadult, and adult. This line of study used a multidisciplinary approach including histology (Nissl and myelin silver staining), revealed the cytoarchitecture in different brain regions, myelination fibers and patterns. Immunohistochemistry (IHC) using markers for neural and glial progenitors (SOX2), cell proliferation (PCNA), astrocytes (GFAP, S100A1), oligodendrocytes (OLIG2), microglia (IBA-1) and immature neurons (DCX). Immunofluorescence double-labeling IHC, which revealed colocalization of neural stem cells and GFAP the in ventricular zones, pial surface, optic tectum and cerebellum. Transmission electron microscopy (TEM) revealed detailed ultrastructural insights into mitochondria, glial and neuronal features. Findings highlight the distribution, characterization, timing, regional differences, and cellular mechanisms of gliogenesis, contributing to a deeper understanding of avian brain development. The study also showed dynamic neuronal and glial population changes during brain maturation and indicate a process of temporal and spatial regulation of gliogenesis during brain maturation. These insights contribute to a greater understanding of cellular dynamics within the quail brain and, thus, are important for our more comprehensive understanding of avian development and brain evolution.