Effects of over-expression of SOD2 in bone marrow-derived mesenchymal stem cells on traumatic brain injury.

Intravenous administration of bone marrow-derived mesenchymal stem cells (BM-MSCs) has been shown to promote nerve cell regeneration following traumatic brain injury (TBI). As the anti-oxidant defense systems in neuronal tissue including superoxide dismutase 2 (SOD2) are crucial to defend cell against oxidative stress. We proposed a new stratege to increase the therapeutic effect of MSCs by preventing cells death from oxidative stress. We overexpressed SOD2 in BM-MSCs, transplanted these MSCs into TBI model mice, assessed the protective effect of SOD2 against oxidation-induced apoptosis in BM-MSCs both in vitro and in vivo, evaluated brain functional recovery by the rotarod behavioral test, and tested the oxidation status of TBI mice brain after BM-MSCs transplantation by monitoring the superoxide dismutase, glutathione and malonaldehyde level. We found over-expression of SOD2 protected BM-MSCs from H2O2-induced cell apoptosis. Injection of SOD2 over-expressed BM-MSCs attenuated neuro-inflammation in the ipsilateral cortex of TBI mice, and protected TBI mice against loss of blood-brain barrier integrity. Furthermore, the rotarod behavioral test showed functional recovery of TBI mice after MSC treatment. Our experiments indicated that SOD2-over-expressed BM-MSCs have an improved therapeutic effect on brain injury treatment in TBI mice.