Neurogenesis and gliogenesis in adult brain using the japanese quail animal model.

Most avian neurogenesis studies have previously focused on the song control system with little attention to non-songbirds. The Japanese quail presented a unique opportunity to establish the peak period when cell proliferation, neurogenesis and gliogenesis, occur during the post hatching ages 3 to 12 weeks and likely time for interruption of these processes. Single labelling for the proliferating cell nuclear antigen (PCNA) and doublecortin (DCX) immunohistochemistry were adopted following heparin administration, transcranial perfusion fixation with 0.9% cold saline solution, then 4% paraformaldehyde (PFA) in 0.1 M phosphate buffer solution. Free frozen sections were cut at 50 μm using a cryostat. For gliogenesis, double labelling immunolocalization for gliogenesis was undertaken with these antibodies; SOX2, DCX, S100, GFAP and Oligo2 and across the juvenile, subadult and adult birds. The PCNA staining was widespread across different brain regions. Numbers of bipolar and multipolar DCX immunoreactive cells were higher in the juvenile compared to subadult and adult quails. DCX was used as a proxy for neuronal incorporation with bipolar and multipolar DCX immunoreactive cells observed in the entire telencephalon except for the entopallium and arcopallium. neuronal incorporation in the quail telencephalon is widespread, peaked at between 5 and 6 weeks before declining with post hatching age. The neuroprogenitor stemlike- positive cells decreases with age in all Sox2 positive regions seen in line with the differentiation process. 3 subtypes of astrocytes designated as unipolar, multipolar and cells with immuno-negative cell body. Some specific brain regions presented colocalization of astrocyte and oligodendrocytes, an indication of concurrent gliogenesis. The Japanese quail provides a good avian model for investigating neurogliogenesis. Single labelling and colocalisation of neurons, astrocytes and oligodendrocytes correlating neurogenesis and gliogenesis at time points with greatest cell proliferation was established. None