The time‐dependency of post‐conditioning for neuroprotection against global cerebral ischemia and reperfusion injury in C57BL/6 mice

Abstract

To establish (a) suitable treatment protocol(s) for neuroprotection in mice, the post‐conditioning treatments were performed by 3 cycles of reperfusion and occlusion (5s/5s, 10s/10s, 15s/15s, 30s/30s and 45s/45s, respectively) on bilateral common carotid artery immediately after 10 min bilateral common carotid artery occlusion (BCCAO) in male C57BL/6 mice. The escape latency was the shortest in Morris water maze test and the recovery of cerebral blood flow after reperfusion was complete in 15s/15s post‐conditioning group while the mice in 30s/30s group performed best in beam walking test. Calcium overload as well as neuron death rate were depressed most significantly in hippocampus and striatum in 15s/15s group and 30s/30s group respectively. Additionally, we tested the neuroprotective efficiency of 15s/15s postconditioning applied at 5min, 15min, 30min or 1h after the reperfusion and found that the protective effect was decreasing when increasing the delay time of postconditioning. Delay for more than 30min eliminated the protective effect of post‐conditioning. We concluded that appropriate post‐conditioning (15s/15s and 30s/30s, 3 cycles) provides better neuroprotection against global cerebral ischemia and reperfusion injury in mice.