MK8719 can alleviate cerebral ischemic injury in rats through STAT6 activating anti-inflammatory microglia

Abstract:

Objective To investigate the effects of MK8719 （an inhibitor of O-linked N-acetylglucosamine［O-GlcNAc］ hydrolase） in a rat model of cerebral ischemic injury.Methods A rat middle cerebral artery occlusion model was established to simulate cerebral ischemia/reperfusion injury. We assessed cerebral infarct volume with 2，3，5-triphenyltetrazolium chloride staining；evaluated neuromotor function using the modified Neurological Severity Score；observed cerebral tissue changes after injury with Nissl staining and HE staining；and assessed the activation of anti-inflammatory microglia by immunofluorescence assay. An in-vitro BV2 microglia-based oxygen and glucose deprivation/re-oxygenation model was established to simulate ischemia-hypoxia/reperfusion injury. We measured the levels of total signal transducer and activator of transcription 6（STAT6），nuclear STAT6，phosphorylated STAT6，and O-GlcNAcylated STAT6 by Western blot；and measured the levels of pro-inflammatory interleukin（IL）-6 and IL-1β and anti-inflammatory IL-10 and transforming growth factor-β（TGF-β） released from microglia by enzyme-linked immunosorbent assay.Results The model rats treated with MK8719 showed a significantly smaller cerebral infarct size，significantly alleviated neurological deficits，and a significantly higher proportion of anti-inflammatory microglia. BV2 cells treated with MK8719 showed significantly increased expression of O-GlcNAcylated STAT6，phosphorylated STAT6（P<0.001），and nuclear STAT6，significantly reduced release of IL-6 and IL-1β（P<0.001），and significantly increased release of IL-10 and TGF-β（P<0.001）.Conclusion MK8719 can produce neuroprotective effects in rats with cerebral ischemic injury，which may be mediated by STAT6 activating anti-inflammatory microglia.