To further analyse, the effects of OEC‐CM on cell cultures, we evaluated the rate of cell growth (RCG) in both normoxic and H/R injured cultures (Fig. 1H–K). Our results demonstrated that in normoxic conditions, cell lines supplemented with 25% OEC‐CM, collected from OECs after 24, 48 and 72 hrs, did not show significant reduction of the RCG. The same effect was observed when cells were grown in 50% OEC‐CM collected after 24 or 48 hrs. In contrast, cultures grown in 50% OEC‐CM, collected after 72 hrs and in 100% of OEC‐CM (all conditioning times), showed a significant decrease of RCG (Fig. 1H and J). Interestingly, all conditioned media used at 25%, 50% and 100% on H/R injured cultures showed a significant increase of RCG compared to control cultures (Fig. 1I and K). Taken together, these findings suggested that, in both normoxic and H/R injured cultures, the cells grown in 48 hrs OEC‐CM mixed 1:1 in maintenance medium, showed a higher protective effect and supported a better RCG. For this reason all further studies have been performed by using 50% OEC‐CM collected after 48 hrs. These findings confirmed that OECs, affecting the media composition, were able to exert neuroprotective actions and to increase cell survival and cell proliferation after injury.