Role of mitochondrial function in the protective effects of ischaemic postconditioning on ischaemia/reperfusion cerebral damage

Objective To investigate the effects of ischaemic postconditioning on brain injury and mitochondria in focal ischaemia and reperfusion, in rats. Methods Adult male Wistar rats (n=15 per group) underwent sham surgery, ischaemia (2-h middle cerebral artery occlusion), or ischaemia followed by ischaemic postconditioning (three cycles of 30s reperfusion/30s reocclusion). Brain infarction size, neurological function, mitochondrial reactive oxygen species (ROS) production, mitochondrial membrane potential and mitochondrial swelling were evaluated 24h postsurgery. Results Infarct size was significantly smaller, and neurological function was significantly better, in the ischaemic postconditioning group than in the ischaemia group. Ischaemia resulted in significant increases in mitochondrial ROS production and swelling, and a reduction in mitochondrial membrane potential, all of which were significantly reversed by postconditioning. Conclusions The protective role of ischaemic postconditioning in focal ischaemia/reperfusion may be due to decreased mitochondrial ROS production, reduced mitochondrial membrane potential and suppressed mitochondria swelling. Mitochondria are potential targets for new therapies to prevent brain damage caused by ischaemia and reperfusion.