Ischemic postconditioning protects against global cerebral ischemia/reperfusion-induced injury in rats.
OBJECTIVE
Ischemic postconditioning has been found to decrease brain infarct area and spinal cord ischemic injury. In this study, we tested the hypothesis that ischemic postconditioning reduces global cerebral ischemia/reperfusion-induced structural and functional injury in rats.


METHODS
Ten-minute global ischemia was induced by 4-vessel occlusion in male Sprague-Dawley rats. The animals underwent postconditioning consisting of 3 cycles of 15-second/15-second (Post-15/15), 30-second/30-second (Post-30/30), or 60-second/15-second (Post-60/15) reperfusion/reocclusion or 15-second/15-second reperfusion/reocclusion applied after a 45-second reperfusion (Post-45-15/15).


RESULTS
Ten minutes of ischemia and 7 days of reperfusion destroyed 85.8% of CA1 hippocampal neurons and 64.1% of parietal cortical neurons. Three cycles of Post-15/15, Post-30/30, and Post-45-15/15 reperfusion/reocclusion markedly reduced neuronal loss after 7 days or 3 weeks of reperfusion and diminished the deficiency in spatial learning and memory. After reperfusion, a period of hyperperfusion followed by hypoperfusion was observed, both of which were blocked by postconditioning. The cytosolic level of cytochrome c increased significantly after 48 hours of reperfusion, and this was inhibited by Post-15/15, Post-30/30, and Post-45-15/15. However, 3 cycles of 60-second/15-second reperfusion/reocclusion failed to protect against neuronal damage, behavioral deficit, or cytochrome c translocation.


CONCLUSIONS
Our data provide the first evidence that an appropriate ischemic postconditioning strategy has neuroprotective effects against global cerebral ischemia/reperfusion injury and a consequent behavioral deficit and that these protective effects are associated with its ability to improve disturbed cerebral blood flow and prevent cytochrome c translocation.
Wang
Jing-ye
JY
Department of Neurology, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Shen
Jia
J
Gao
Qin
Q
Ye
Zhi-guo
ZG
Yang
Shui-you
SY
Liang
Hua-wei
HW
Bruce
Iain C
IC
Luo
Ben-yan
BY
Xia
Qiang
Q
D000818:Animals; D002545:Brain Ischemia / Q000473:pathology* / Q000503:physiopathology* / Q000523:psychology; D002452:Cell Count; D002560:Cerebrovascular Circulation; D045304:Cytochromes c / Q000378:metabolism; D019610:Cytoprotection; D003600:Cytosol / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology; D019194:Ischemic Preconditioning / Q000379:methods; D008297:Male; D018782:Maze Learning; D008568:Memory; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D010296:Parietal Lobe / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000473:pathology* / Q000503:physiopathology* / Q000523:psychology; D013550:Swimming; D013997:Time Factors
D045304:Cytochromes c