Effects of olfactory ensheathing cells on the proliferation and differentiation of neural stem cells

BACKGROUND: Olfactory ensheathing cells can promote oriented differentiation and proliferation of neural stem cells by cell-secreted neural factors. OBJECTIVE: To observe the effect of olfactory ensheathing cells on the differentiation and proliferation of neural stem cells. DESIGN, TIME AND SETTING: Cytology was performed at the Department of Neurology, Tongji Medical College, Huazhong University of Science and Technology, China, from September 2007 to October 2008. MATERIALS: Mouse anti-nestin polyclonal antibody (Chemicon, USA), mouse anti-glial fibrillary acidic protein (GFAP) IgG(1), mouse anti-2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) IgG(1), mouse anti-Tubulin Class-III IgG(1) (Neo Markers, USA), Avidin-labeled Cy3 (KPL, USA), and goat anti-mouse IgG(1): fluorescein isothiocyanate (FITC) (Serotec, UK) were used in this study. METHODS: Tissues were isolated from the embryonic olfactory bulb and subependymal region of Wistar rats. Serum-free DMEM/F12 culture media was used for co-culture experiments. Neural stem cells were incubated in serum-free or 5% fetal bovine serum-containing DMEM/F12 as controls. MAIN OUTCOME MEASURES: After 7 days of co-culture, neural stem cells and olfactory ensheathing cells underwent immunofluorescent staining for nestin, tubulin, glial fibrillary acidic protein, and CNPase. RESULTS: Olfactory ensheathing cells promoted proliferation and differentiation of neural stem cells into neuron-like cells, astrocytes and oligodendrocytes. The proportion of neuron-like cells was 78.2%, but the proportion of neurons in 5% fetal bovine serum DMEM/F12 was 48.3%. In the serum-free DMEM/F12, neural stem cells contracted, unevenly adhered to the glassware wall, or underwent apoptosis at 7 days. CONCLUSION: Olfactory ensheathing cells promote differentiation of neural stem cells mainly into neuron-like cells, and accelerate proliferation of neural stem cells. The outcome is better compared with serum-free medium or medium containing 5% fetal bovine serum.