Document Detail

Chronic and intermittent hypoxia induce different degrees of myocardial tolerance to hypoxia-induced dysfunction.
MedLine Citation:
PMID:  12037128     Owner:  NLM     Status:  MEDLINE    
Chronic hypoxia (CH) is believed to induce myocardial protection, but this is in contrast with clinical evidence. Here, we test the hypothesis that repeated brief reoxygenation episodes during prolonged CH improve myocardial tolerance to hypoxia-induced dysfunction. Male 5-week-old Sprague-Dawley rats (n = 7-9/group) were exposed for 2 weeks to CH (F(I)O(2) = 0.10), intermittent hypoxia (IH, same as CH, but 1 hr/day exposure to room air), or normoxia (N, F(I)O(2) = 0.21). Hearts were isolated, Langendorff perfused for 30 min with hypoxic medium (Krebs-Henseleit, PO(2) = 67 mmHg), and exposed to hyperoxia (PO(2) = 670 mm Hg). CH hearts displayed higher end-diastolic pressure, lower rate x pressure product, and higher vascular resistance than IH. During hypoxic perfusion, anaerobic mechanisms recruitment was similar in CH and IH hearts, but less than in N. Thus, despite differing only for 1 hr daily exposure to room air, CH and IH induced different responses in animal homeostasis, markers of oxidative stress, and myocardial tolerance to reoxygenation. We conclude that the protection in animals exposed to CH appears conferred by the hypoxic preconditioning due to the reoxygenation rather than by hypoxia per se.
Giuseppina Milano; Antonio F Corno; Silvio Lippa; Ludwig K Von Segesser; Michele Samaja
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Experimental biology and medicine (Maywood, N.J.)     Volume:  227     ISSN:  1535-3702     ISO Abbreviation:  Exp. Biol. Med. (Maywood)     Publication Date:  2002 Jun 
Date Detail:
Created Date:  2002-05-30     Completed Date:  2002-06-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100973463     Medline TA:  Exp Biol Med (Maywood)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  389-97     Citation Subset:  IM    
Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
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MeSH Terms
Heart / physiology
Myocardium / metabolism*
Oxidative Stress
Rats, Sprague-Dawley
Time Factors
Ubiquinone / blood
alpha-Tocopherol / blood
Reg. No./Substance:
1339-63-5/Ubiquinone; 59-02-9/alpha-Tocopherol

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