Isolation and characterization of neural stem cells from fetal canine spinal cord.

Neurogenesis in adult mammals occurs mainly in the subventricular and subgranular areas of the brain, but there are also reports of its occurrence in the spinal cord. In a study on rats, neural stem cells and neuroprogenitor cells could be obtained through primary spinal cord culture, but there are no studies on these cells in canine species, to date. Dogs represent an appropriate animal model for studies on neurogenesis and neurological disorders. In addition, they are animals of great affective value, and the therapeutic use of neural stem cells can represent a breakthrough in regenerative veterinary medicine. Therefore, this study aimed to determine a protocol for the isolation, culture, and characterization of neural and neuroprogenitor stem cells derived from the spinal cord of canine fetuses. The cells were isolated from spinal cord fragments and cultured in serum-free culture medium supplemented with EGF and FGF-2 growth factors. These cells were observed daily by optical microscopy to analyze their morphological characteristics. From the third day in vitro, it was possible to observe translucent cell groupings, similar to the neurospheres, which approximately ranged from 50 µm to 200 µm at seven days in vitro. Throughout the culture period, the neurospheres developed ribbons in their periphery that migrated and communicated with other neurospheres. RT-PCR revealed that the cells expressed the characteristic genes SOX2, NESTIN, and GFAP. In addition to gene expression, the cells were phenotypically marked in the immunofluorescence assay for the proteins Nestin, GFAP, and β-tubulin III, characterizing them as neurospheres. Our results suggest that the spinal cord may be a source of neural stem cells and neural progenitor cells in canine fetuses. These cells may be an interesting option for neurogenesis and neuroregenerative therapy studies.