[Isolation and cultivation of neural stem cells from the embryonic rat brain and spinal cord]

The aim of this study was to establish the culture system of isolation and cultivation of the neural stem cells (NSCs) from the embryonic rat brain and spinal cord. The methods of microscopic dissection, cell culture and immunofluorescence cytochemistry were used. The results are as follows. (1) In the presence of fibroblast growth factor-2 (FGF-2) and epidermal growth factor (EGF), both brain- and spinal cord-derived stem cells proliferated and expanded in vitro for 8 - 10 passages (over 60 d). The period of expansion resulted in a 10(6)-fold increase in brain-derived NSCs and 10(5)-fold increase in spinal cord-derived NSCs. These proliferating cells expressed nestin. (2) In the medium containing 1% FBS, the two NSCs populations could be induced to differentiate into neurons, astrocytes and oligodentrocytes. The percentage of neurons (beta-tubulin III-ir) differentiated from brain-derived NSCs decreased rapidly from 11.95+/-2.5% at passage 2 (P(2)) to 1.97+/-1.16% at passage 5 (P5). Significant difference was shown between P(2) and P(5) (P<0.01). The percentage of oligodentrocytes (Rip-ir) differentiated from brain-derived NSCs remained mostly unchanged from 8.66+/-2.93% at P(2) to 9.12+/-1.13% at P(5). The same differentiation patterns were found in spinal cord-derived NSCs. All these results indicate that both embryonic rat brain- and spinal cord-derived NSCs can expand and proliferate in vitro through multiple passages, and retain the capacity to differentiate into all three major types of cells in the central nervous system.