Connexin involvement in the protective effect of Olfactory Ensheathing Cells conditioned medium in SH-SY5Y Cell Line during hypoxia/re-oxygenation stress.

It has been demonstrated that the expression of connexins (Cxs), the core proteins of gap junctions and hemichannels, are involved in neuroprotection in stress conditions. Olfactory Ensheathing Cells (OECs), a special population of glial cells sharing properties with both Schwann cells and astrocytes, are in able to synthesise several trophic factors exerting a neuroprotective action and promoting growth and functional recovery both in vivo and in vitro models. In this study, SH-SY5Y cells were cultured in medium supplemented with different percentages of OECs-conditioned medium. Following hypoxia/re-oxygenation and serum deprivation stress, we investigated cell viability through MTT assay and Cxs expression by immunocytochemistry. The results showed that compared to controls OECs-conditioned medium protected both hypoxic or serum deprivation cultures. Moreover, Cx36 and Cx43 showed a dynamic expression that likely suggests their implication in cell survival and proliferation. These evidences configure connexins like an important player in neuroprotection against hypoxic and serum deprivation conditions.