Olfactory ensheathing cells exert a trophic effect on the hypothalamic neurons in vitro

Olfactory ensheathing cells (OECs) constitute an usual population of glial cells sharing properties with both Schwann cells (SC) of peripheral nervous system (PNS) and astrocytes of the central nervous system (CNS). They express a high level of growth factors which play a very important role as neuronal support. Recent evidence in literature suggests that OECs may facilitate axonal regeneration in the injured nervous system. In this study, we developed an in vitro model to evaluate the neurotrophic effect of OECs on the survival and axonal outgrowth of hypothalamic neurons. Co-cultures of OECs and hypothalamus neuronal cells of postnatal rats were successfully established and cells were immunocytochemically characterized. Furthermore, some neuronal cultures were added with NGF, bFGF and GDNF to compare with the co-cultures. Our results indicate that in co-cultures of hypothalamic neurons and OECs, the number of neurons was significantly increased compared to control cultures exhibiting a dense axonal outgrowth. Moreover, we show that NGF promoted a major neuronal survival than bFGF and GDNF, while bFGF and GDNF exerted an evidence axonal and dendritic outgrowth compared to NGF. In conclusion, these data suggest that OECs have the capacity to promote the survival and axonal outgrowth of hypothalamic neurons in vitro and that bFGF, NGF and GDNF differentially support hypothalamic neurons promoting and enhancing the neuronal survival and outgrowth. Therefore, the OECs are a source of growth factors and might be considered a better approach for functional recovery and growth factors might exert a neuroprotective effect in neurodegenerative disorders.