Olfactory ensheathing cells represent an optimal substrate for hippocampal neurons: an in vitro study

Olfactory ensheathing cells (OECs) are cells that display Schwann cell or astrocyte-like properties. They are a source of growth factors and adhesion molecules which play a very important role as neuronal support enhancing cellular survival. Over the past 10 years, OECs have emerged as a leading reparative candidate, when transplanted into the injured spinal cord, having shown significant promise in the regeneration of spinal cord lesions. In this study we assessed the efficacy of OECs on the survival and neurite outgrowth of hippocampal neurons in vitro. Co-cultures of OECs and hippocampal of postnatal rats were successfully established and cells were immunocytochemically characterized. Some hippocampal cultures were added with growth factors, as bFGF, NGF and GDNF. Furthermore, conditioned medium from OECs cultures was used to feed some hippocampal neurons coverslips. Our results show that in co-cultures of hippocampal neurons and OECs the number of neurons and their neurite outgrowth were significantly increased in comparison with controls. Moreover, we showed that NGF and GDNF promoted a more positive effect in both neuronal survival and neurite outgrowth than bFGF. OEC-conditioned media stimulated both the neuronal survival and dense neurite outgrowth. These data indicate that OECs, as a source of growth factors, can promote the survival and the neurite outgrowth of hippocampal neurons in vitro and that bFGF, NGF and GDNF support them differently. Therefore, as OECs and their secreted growth factors appear to exert a neuroprotective effect for functional restoration and for neural plasticity in neurodegenerative disorders, they might be considered an approach for functional recovery.