Abstract: Objective To observe the morphological changes during development of the ventricular zone (VZ) and
subventricular zone (SVZ) of human fetus and the distribution pattern of neural stem cells in the VA and SVZ. Methods
Human fetuses at the gestational ages of 9-11 weeks, 14-16 weeks, 22-24 weeks and 32-36 weeks were collected, and the brain
sections of the VZ/SVZ under the frontal lobe were examined for cytoarchitecture and distribution of nestin-positive cells with
HE staining, immunohistochemistry or immunofluorescence. Results The thickness of VZ underwent no significant changes at
the gestational ages of 9-24 weeks (P>0.05) and became obviously thinner at 32 weeks (P<0.05), while the thickness of SVZ
increased during 9-24 weeks (P<0.05) without obvious thinning at 32 weeks (P>0.05). VZ was thicker than SVZ at 9-11 weeks
but became markedly thinner than SVZ after 14 weeks (P<0.05). The VZ contained denser cells than SVZ and showed a distinct
boundary between the VZ and SVZ. Large numbers of nestin-positive cells were detected in the VZ and SVZ, and nestin
immunoreactivity was found primarily in the cell processes and occasionally in the soma. Some nestin-positive cells in the SVZ
had 1-3 processes. Nestin immunoreactivity in the VZ and SVZ gradually grew weak with development. The cells positive for
both nestin and Ki67 were located mainly in the inner zone of the VZ and throughout the SVZ, where some nestin-positive but
Ki67-negative cells were also found. Conclusion The SVZ fully extends and the neural stem cells in the VZ/SVZ can be
morphologically heterogeneous during the development of fetal human brain.