Abstract: Objective To observe the influence of transient hypoxia on the expression of neurogenic differentiation factor(NeuroD) in cultured neurons and investigate its possible roles in neural regeneration. Methods Influence of transient hypoxia on the expression of NeuroD was analyzed on the outcome of embryonic rat neurons in culture. Cultures at five days were exposed to hypoxia. After different periods(3 hours, 6 hours) of hypoxia, RT-PCR was performed to examine the mRNA levels of NeuroD. Electron microscopy was performed to observe neuronal alterations. Dishes after 3 hours hypoxia were then returned to normal atmosphere for ensuing culture 96 hours. Immunohistochemistry was performed to examine cell proliferation by incorporation of 5-bromodeoxyuridine(BrdU). Results Following hypoxia for 3 hours in cultured neurons, NeuroD increased distinctly and the incorporation of BrdU revealed an accumulation of proliferating cells.Compared with the control group, NeuroD showed no much difference after hypoxia for 6 hours(EM>P/EM>>0.05). Neurons exposing hypoxia for 6 hours were damaged by electron microscope. Conclusion The expression of NeuroD increases post asphyxia in cultured neurons, following with cell proliferation. NeuroD seems to play a role in the process of neurogenesis.

Key words: Transient hyposia, Hippocampal neuron, Neurogenic differentiation, Neurogenesis, Electron microscopy, RT-PCR, Immunohistochemistry, Rat