Limb remote ischemic post-conditioning mitigates brain recovery in a mouse model of ischemic stroke by regulating reactive astrocytic plasticity

Abstract

Maladaptive alterations of astrocytic plasticity may cause brain edema in the acute stage of stroke and glial scar formation in the recovery stage. The present study was designed to investigate the potential regulation of limb remote ischemic post-conditioning (RIPC) on astrocytic plasticity in experimental cerebral ischemia-reperfusion injury. Cerebral ischemia was induced by transient middle cerebral artery occlusion (tMCAO) for 1 h in C57BL/6 mice, who were treated with RIPC immediately after reperfusion. The results showed that RIPC decreased hemispheric swelling, infarct volume and brain atrophy, and increased neurological function recovery and survival rates of ischemic mice at 3 and 14 d after cerebral ischemia-reperfusion, respectively. Moreover, the proportion of astrocyte subtypes was adjusted by RIPC treatment, demonstrated by decreased expression of the fibrous type (glial fibrillary acidic protein, GFAP) and increased expression of the protoplasmic type (glutamine synthetase, GS) in the ipsilateral side of the mouse brain at 14 d after cerebral ischemia-reperfusion. RIPC treatment adjusted the proportion of GFAP subtypes by downregulating the protein level of GFAPα, as well as upregulating the GFAPδ/GFAPα ratio in the ipsilateral side at 3 and 14 d after reperfusion. Notably, RIPC inhibited the phosphorylation of signal transducer and activators of transcriptions 3 (p-STAT3) in the ipsilateral side at 3 and 14 d after cerebral ischemia-reperfusion. Taken together, the results show that RIPC treatment could regulate reactive astrocytic plasticity and inhibition of STAT3 phosphorylation to promote neurological function recovery following ischemic stroke.

Keywords: Astrocytic plasticity; GFAP; Ischemic stroke; RIPC; STAT3.