Abstract W MP76: Ischemic Postconditioning Protected Against Stroke by Inhibiting NADPH Oxidase-Mediated ROS Activity
Background: The underlying protective mechanisms of ischemic postconditioning (IPostC) remain elusive. Although previous studies have shown that IPostC generates protection by attenuating ROS activity, how this protection is achieved is not known. We hypothesize that inhibition of NADPH oxidase-mediated reactive oxygen species (ROS) is essential for the neuroprotective effects of IPostC.
Methods: We used both wild type mice and mice mutant for the NADPH oxidase gene. Stroke was induced by middle cerebral artery (MCA) suture occlusion and IPostC was conducted by repeated, brief occlusions immediately after reperfusion. Glucose was injected to promote NADPH oxidase, while apocynin and 2-deoxyglucose (2-DG) were used to inhibit it. FACS was used to quantify inflammatory cells in the brain, and to assess ROS activity in macrophage/microglia subsets stained by 2′-7′-dichlorodihydrofluorescein diacetate (DCFH-DA).
Results: IPostC reduced infarction as a function of the numbers of cycles of brief MCA occlusion. Glucose injection enlarged the infarction induced by the control stroke and abolished the protective effects of IPostC. Both 2-DG and apocynin injection reduced infarction, but only apocynin, and not 2-DG, acted synergistically with IPostC against stroke. Moreover, neither IPostC nor glucose altered the infarction in NADPH oxidase gene mutated mice. FACS results suggest that glucose injection exacerbated while IPostC inhibited inflammatory cell infiltration. Furthermore, IPostC blocked ROS activity in both macrophages and microglia.
Conclusions: IPostC attenuated infarction by inhibiting NADPH oxidase-mediated ROS activity.
Author Disclosures: S. Joo: None. W. Xie: None. Y. Fan: None. H. Zhao: None.
- © 2014 by American Heart Association, Inc.