Remote ischemic preconditioning (RIPC), which consists of several brief ischemia/reperfusion applied at the remote site of lethal ischemia reperfusion, can, through activating different mechanisms, increase the ability of the body's endogenous protection against prolonged ischemia/reperfusion. Recent studies have shown that RIPC has neuroprotective effects, but its mechanisms are not well elucidated. The present study aimed to determine whether activation of KATP channels in remote renal preconditioning decreases hippocampus damage induced by global cerebral ischemia. RIPC was induced by ischemia of the left renal artery (IPC); 24 h later, global cerebral ischemia reperfusion (IR) was induced by common carotid arteries occlusion. 5hydroxydecanoate (5HD) and glibenclamide (Gli) were injected before of IPC. The levels of malondialdehyde (MDA) and catalase (CAT) activity were assessed in hippocampus. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) was assessed to detect apoptotic cells in hippocampus. RIPC inhibited apoptosis by decreasing positive TUNEL cells (P < 0.05). KATP channels blocking with 5HD and Gli markedly increased apoptosis in hippocampal cells in RIPC group (P < 0.001). RIPC decreased MDA level and increased CAT activity in ischemic hippocampus (P < 0.01). Also, 5HD and Gli inhibited the effect of RIPC on MDA level and CAT activity (P < 0.05). The present study shows that RIPC can effectively attenuate programmed cell death, increase activity of CAT, and reduce MDA levels. Blocking of KATP channels inhibited the protective effects of RIPC.
Keywords: Apoptosis; Hippocampus; KATP channels; Remote ischemic preconditioning.