Neuroglial cells in long-term primary cultures from the gilthead seabream (Sparus aurata L.): new functional in vitro model from bony fish brain.

As its Greek name suggests, neuroglia is the glue of the nervous system, simply referred to as non-neuronal cells, with supporting functions for neurons in the central nervous system (CNS) of mammalian and lower vertebrates. Recent advances in stem cell biology have redefined new functions. In fish, neuroglial cells have been described as supporting cells, and as such require further investigation. Approximately 283 cell lines have been obtained from fish worldwide, yet none from the brain of Sparus aurata, neither in cell lines nor as primary culture. We describe a novel reproducible in vitro neuroglial marine model for establishing primary neuroglial cell cultures by dissociating the whole brain of seabream juveniles. Proliferating neural stem cells produced alongside three generating lineages (neuronal precursor cells, astroglial precursor cells and oligodendroglia precursor cells) developed neurons, astrocytes and oligodendrocytes, respectively. The radial glia, finely described by morphological studies and immunochemical antigen expression, showed a particular spatial distribution, giving rise simultaneously both to astrocytes and neuronal precursors within a highly proliferative assemblage. Radial glial cells were assessed by glial fibrillary acidic protein (GFAP) and vimentin reactivity, astrocytes by GFAP, neurons by the neuron-specific markers for ubiquitin carboxy-terminal hydrolase 1 (UCHL1) and intermediate filament associated protein (NF). Myelinating oligodendrocytes were immunostained with anti-myelin basic protein (MBP) and anti-O4. Findings suggest that seabream neuroglial cells at 3-4 weeks of culture proliferation acquire neuroglial differentiation and oligodendrocyte maturation with myelination, suggesting that mixed neuroglial cultures accelerate maturation of oligodendrocytes and regenerate CNS injury in fish.