Abstract 3162: Enhancement Of Antioxidative Activity Facilitates Cell Transplantation Therapy For Stroke
Background: Recent studies show that neural stem cells (NSCs) transplanted in the brain provide a potential therapy not only for ischemic stroke, but also for hemorrhagic stroke. However, the low survival rate of grafted NSCs in the brain might preclude a therapeutic effect. We focused on the effect of oxidative stress against grafted cells and hypothesized that conferring antioxidant properties to the NSCs before transplantation into the host tissue may overcome cell death in the hostile host environment and enhance neuroprotection after transplantation.
Methods: NSCs were obtained from the striatum of copper/zinc-superoxide dismutase (SOD1) transgenic mice, manganese-superoxide dismutase (SOD2) transgenic mice and wild-type mice. The NSCs were exposed to several kinds of oxidative stress (oxygen-glucose deprivation and reoxygenation, hemoglobin, H2O2, NO), and preconditioning was performed before exposure to oxidative stress. Preconditioning with IL-6 induced SOD2 up-regulation via Janus activating kinase-signal transducer activator of transcription 3 in NSCs and preconditioning with minocycline up-regulated Nrf-2, which is a crucial component of the endogenous antioxidant system. Cell viability was assessed with LDH assay, WST-1 assay and TUNEL staining. To examine survival of the grafted cells in the ischemic region in vivo, they were transplanted into the cortical ischemic penumbra 6 hours after ischemia, and TUNEL staining was performed 2 days after transplantation. Neurological evaluation was performed before and 1, 7, 14, 21 and 28 days after transplantation.
Results: Death of transgenic (SOD1 and SOD2) NSCs and preconditioned (PC) NSCs was significantly decreased compared with wild-type non-PC NSCs after exposure to oxidative stress. Furthermore, these NSCs showed that hydroethidine signals, which represent superoxide production, were suppressed under oxidative conditions. Preconditioning reduced the number of TUNEL-positive grafted cells in the ischemic brain 2 days after transplantation compared with non-PC NSCs (IL-6 by 40%, n=4, p<0.005; minocycline by 76%, n=4, p<0.001). Minocycline PC NSCs also showed a significant reduction in infarct volume (by 15%, n=7, p<0.05, cortex lesion size/contralateral) and showed functional recovery from 1 through 28 days after transplantation compared with the non-transplanted control group (n=7).
Conclusion: Our results suggest that enhanced antioxidative activity in NSCs before transplantation provides improved survival of NSCs in the stroke brain. The increased survival of these NSCs may provide therapeutic potential for neuroprotection in stroke patients.
- © 2012 by American Heart Association, Inc.