A Combination of Remote Ischemic Perconditioning and Cerebral Ischemic Postconditioning Inhibits Autophagy to Attenuate Plasma HMGB1 and Induce Neuroprotection Against Stroke in Rat.

Remote ischemic perconditioning (RIPerC) and ischemic postconditioning (IPOC) are well-acknowledged neuroprotective procedures during ischemic injury. The present study established a combined RIPerC and IPOC (RIPerC + IPOC) model in rats and studied how it would regulate the autophagy process and affect HMGB1 levels in a rat model of middle cerebral artery occlusion (MCAO). Rats with MCAO were treated with RIPerC by fastening and release of the left hind limb to achieve 4 cycles of 5 min remote ischemia reperfusion, 40 min prior to cerebral reperfusion, and then treated with IPOC by exposing the cerebral middle artery to 3 cycles of 30 s reperfusion/30 s occlusion at the onset of cerebral reperfusion. Infarction volumes, neurological deficits, and pathological changes were assessed 24 h after ischemia. The autophagy activator rapamycin (RAP) and the autophagy inhibitor 3-methyladenine (3-MA) were administrated for further mechanism. The expression and location of HMGB1 and the autophagy-related proteins like LC3, Beclin1, and P62 as well as plasma HMGB1 levels were measured. Our results suggested that RIPerC + IPOC attenuated plasma HMGB1 levels to intensify its neuroprotective effect against cerebral ischemic reperfusion injury via inhibiting the autophagy process.