MGMT-Mediated neuron Apoptosis in Injured Rat Spinal Cord

•MGMT expression was increased following SCI.•Increased MGMT expression mainly located in neuron cells.•Knockdown of MGMT reduced expression of apoptosis-related genes after H2O2 treatment.•Knockdown of MGMT promote neuron survival and function recovery after SCI. Spinal cord injury (SCI) induces a series of endogenous biochemical changes that lead to secondary degeneration, including apoptosis. The aim of this study was to investigate the potential effect and mechanism of action of MGMT in strengthing neuronal apoptosis following SCI. To determine MGMT-mediated apoptosis in spinal cord injury, we performed western blot and analyzed the expression change of MGMT with different timepoints. Western blot analysis showed the upregulation of MGMT has a peak at 21 days in injured spinal cord tissues. Expression and location was observed in the neurons after SCI. Upregulation of p53, Bax, cleaved caspase3 and cleaved caspase9 and downregulation of Bcl2 were detected after SCI. Co-localization of cleaved caspase3 with MGMT indicated MGMT involved in apoptosis taking place after SCI. In addition, we carried out H2O2 stimulation to further confirm MGMT played a role in neuron apoptosis process and activated p53 signaling pathway in vitro. Finally, based above data, we packaged lenti-associated virus inhibit MGMT expression and injected into rat spinal cords after SCI model was built. LV-MGMT not only reduces the neuron apoptosis, but also increases GAP43 expression and promotes hindlimbs locomotor function recovery. Taken together, the in vivo data and the in vitro observations prove MGMT-mediated apoptosis in the injured spinal cord.