Synergistic protection of RGCs by olfactory ensheathing cells and alpha-crystallin through regulation of the Akt/BAD Pathway

Abstract

Our recent in vivo studies have shown that olfactory ensheathing cells (OECs) and α-crystallin can promote retinal ganglion cell (RGC) survival and axonal regeneration synergistically after optic nerve injury. However, the mechanism is still unknown. Here, we studied the synergistic effect and mechanism of OECs and α-crystallin on RGC survival after H2O2-induced oxidative damage and a crushing injury to the optic nerve in an adult rat model. After H2O2-induced oxidative damage, RGC-5 cells were treated with OECs, α-crystallin or a combination of OECs and α-crystallin. Apoptosis of RGC-5 cells was assessed by flow cytometry. Phosphorylated Akt, BAD, and cleaved-caspase3 were detected by Western blot after optic nerve injury in vivo and H2O2-induced RGC-5 oxidative damage in vitro. The results showed that OECs and α-crystallin could both independently inhibit RGC-5 apoptosis (P<0.01), increase the phosphorylation of both Akt and BAD, and decrease the activation of caspase-3 (P<0.01). However, the effect of the combination of both was more significant than either alone. These findings indicate that inhibition of superoxide damage to RGCs through regulation of the Akt/BAD pathway is one of the mechanisms by which OECs and α-crystallin promote optic nerve recovery after injury.