| Cardioprotection by postconditioning in conscious rats is limited to coronary occlusions <45 min. | |
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MedLine Citation:
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PMID: 16815986 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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OBJECTIVES: Brief episodes of ischemia and reperfusion after a lethal ischemic insult confer cardioprotection, a phenomenon termed "ischemic postconditioning." However, all studies reported to date have been conducted in open-chest animal models. We sought to determine whether postconditioning occurs in conscious animals and whether it protects against severe myocardial injury. METHODS: Chronically instrumented rats were assigned to a 30- (Subset 1), 45- (Subset 2), or 60-min (Subset 3) coronary occlusion followed by 24 h of reperfusion. In each subset, rats received no further intervention (control), were preconditioned with 12 cycles of 2-min occlusion/2-min reperfusion immediately (early preconditioning; EPC) or 24 h (late preconditioning; LPC) before myocardial infarction, or were postconditioned with 20 cycles of 10-s occlusion/10-s reperfusion immediately after myocardial infarction (20-10 PostC). RESULTS: With a 30-min occlusion, infarct size (54.4 +/- 2.3% of risk region in control-30) was significantly reduced in EPC-30, LPC-30, and 20-10 PostC-30 groups (by 72, 70, and 47%, respectively; all P < 0.05 vs. control-30). With a 45-min occlusion, infarct size (62.2 +/- 2.4% in control-45) was reduced in EPC-45 and LPC-45 groups (by 47 and 41%, respectively; all P < 0.05 vs. control-45) but not in the 20-10 PostC-45 group [55.4 +/- 2.3%, P = not significant (NS) vs. control-45]. With a 60-min occlusion, infarct size (72.7 +/- 2.2% in control-60) was reduced in the EPC-60 (by 20%, P < 0.05) but not in the LPC-60 (63.6 +/- 2.5%, P = NS) or in the 20-20 PostC group (71.5 +/- 3.4%, P = NS). CONCLUSIONS: Both early and late ischemic preconditioning as well as ischemic postconditioning confer protection in conscious rats; however, unlike early preconditioning, postconditioning protects only against coronary occlusions <45 min. In the conscious rat, the cardioprotection afforded by postconditioning is limited to mild to moderate myocardial injury. |
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Authors:
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Xian-Liang Tang; Hiroshi Sato; Sumit Tiwari; Buddhadeb Dawn; Qiuli Bi; Qianhong Li; Gregg Shirk; Roberto Bolli |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2006-06-30 |
Journal Detail:
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Title: American journal of physiology. Heart and circulatory physiology Volume: 291 ISSN: 0363-6135 ISO Abbreviation: Am. J. Physiol. Heart Circ. Physiol. Publication Date: 2006 Nov |
Date Detail:
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Created Date: 2006-10-10 Completed Date: 2007-01-12 Revised Date: 2007-12-03 |
Medline Journal Info:
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Nlm Unique ID: 100901228 Medline TA: Am J Physiol Heart Circ Physiol Country: United States |
Other Details:
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Languages: eng Pagination: H2308-17 Citation Subset: IM |
Affiliation:
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Division of Cardiology, Univ. of Louisville, Louisville, KY 40202, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Consciousness Coronary Disease / physiopathology*, prevention & control* Creatine Kinase / blood Electrocardiography Ischemic Preconditioning, Myocardial* Male Myocardial Infarction / pathology, prevention & control Myocardial Reperfusion Random Allocation Rats Rats, Inbred F344 Time Factors |
| Grant Support | |
ID/Acronym/Agency:
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R01-HL-55757/HL/NHLBI NIH HHS; R01-HL-68088/HL/NHLBI NIH HHS; R01-HL-70897/HL/NHLBI NIH HHS; R01-HL-74351/HL/NHLBI NIH HHS; R01-HL-76794/HL/NHLBI NIH HHS; R01-HL-78825/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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EC 2.7.3.2/Creatine Kinase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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