MiR-29b expression is associated with a dexmedetomidine-mediated protective effect against oxygen-glucose deprivation-induced injury to SK-N-SH cells in vitro

Ischemic cerebral stroke is a leading cause of death and long-term disability world-wide. Neuronal injury following cerebral ischemia initiates a complex series of signaling cascades that lead to neuronal cell death. MicroRNA 29b (miR-29b) has reported involvement in the pathogenic process of ischemic brain injury. Dexmedetomidine (Dex) is a highly selective (2) adrenergic receptor stimulant that exerts a protective effect on brain tissue. To determine whether Dex might directly influence miR-29b expression after an ischemic injury, human neuroblastoma SK-N-SH cells were subjected to oxygen-glucose deprivation (OGD) for the purpose of creating a neuronal injury model that mimics the effects of brain ischemia in vitro. Next, the association of miR-29b with the protective effect of Dex against ischemic brain injury was studied through the enhancement or inhibition of miR-29b expression by transfection with an miR-29b mimic or inhibitor. We demonstrated that Dex treatment could reduce miR-29b expression, increase cell viability, and inhibit cell apoptosis in the OGD-induced neuronal injury model in vitro. Furthermore, down-regulation of miR-29b expression produced effects on OGD-induced neuronal injuries that were similar to those produced by Dex treatment. Moreover, up-regulation of miR-29b reversed the protective effect of Dex treatment against OGD-induced neuronal injury. Therefore, down-regulation of miR-29b expression might play a role in anti-apoptotic signaling similar to that played by Dex. Elucidation of the role played by miR-29b in ischemia, and identification of a definite association between Dex and miR-29b may lead to the development of new strategies for treating ischemic brain injuries.