[Isolation of neural stem cells from the spinal cords of human fetus.]

Neural stem cells are a potential therapeutic source for cellular transplantation therapy in neurological diseases. The present paper was aimed to investigate whether neural stem cells could be obtained from the spinal cords of low temperature preserved abortuses. Fourteen weeks old abortuses were stored in a refrigerator at 4 degrees C without any additional treatments for 2, 6 and 12 h before use. The spinal cords were anatomized out and divided into cervical cords, thoracic cords and lumbar/sacral cords. Then the spinal cord segments were used for cell culture separately. Neural stem cells were isolated from the segments and cultured in bFGF, EGF and N2 supplement containing free-serum DMEM/F12 (1:1) medium. In order to examine the differentiation potential, the stem cells were induced to differentiate with 5% fetal bovine serum on poly-l-lysine substrate. Clonal culture was carried out to demonstrate that the isolated cells met the standard of stem cells. Indirect fluorescent immunocytochemistry was used to examine the expressions of neural stem cell marker (nestin), neuron marker (MAP2), astrocyte marker (GFAP) and cholinergic marker (ChAT). The stem cells in different cultures were compared. One-way analysis of variance and Kruskal-Wallis test were used for the statistical comparison. As a result, neural stem cells were obtained from all the spinal cord segments with different postmortem intervals. Both the cells on the surface and inside the neurospheres showed nestin immunoreactivity. Therefore, nearly all the cells that composed the neurospheres were nestin-positive undifferentiated cells. When the spheres were induced to differentiate, they could yield GFAP-positive astrocytes and MAP2-positive neurons including ChAT-positive cholinergic neurons. Primary neurospheres could be dissociated mechanically, expand in subcultures and maintain the differentiation potential. In clonal cultures, single cells from a single primary sphere could give rise to new neurospheres, which had the same differentiation potential as the primary spheres. The lumbar/sacral cord cultures gave rise to the most abundant primary neurospheres. When the preservation time of the fetus was prolonged to 12 h, the number of primary neurospheres decreased sharply. The clonal formation and phenotype capacity were similar in all cultures. In conclusion, spinal neural stem cells can be isolated from low temperature preserved abortuses and represent an alternative source for experimental and potential therapeutic purposes.