Ischemic preconditioning attenuates acidosis and postischemic dysfunction in isolated rat heart

The hypothesis that brief ischemia (preconditioning) protects the isolated heart from prolonged global ischemia was tested. Isovolumic rat hearts were preconditioned with either 5 min of ischemia followed by 5 min of perfusion (P1) or two 5-min episodes of ischemia separated by 5 min of perfusion (P...

Full description

Saved in:
Bibliographic Details
Published inThe American journal of physiology Vol. 263; no. 3 Pt 2; p. H887
Main Authors Asimakis, G K, Inners-McBride, K, Medellin, G, Conti, V R
Format Journal Article
LanguageEnglish
Published United States 01.09.1992
Subjects
Acidosis - metabolism
Animals
Coronary Circulation
Coronary Disease - physiopathology
Heart - physiopathology
Hemodynamics
In Vitro Techniques
Male
Myocardial Contraction
Myocardial Reperfusion
Myocardium - metabolism
Rats
Rats, Sprague-Dawley
Online AccessGet more information

Cover

More Information
Summary:The hypothesis that brief ischemia (preconditioning) protects the isolated heart from prolonged global ischemia was tested. Isovolumic rat hearts were preconditioned with either 5 min of ischemia followed by 5 min of perfusion (P1) or two 5-min episodes of ischemia separated by 5 min of perfusion (P2). Control hearts received no preconditioning. All hearts received 40 min of sustained ischemia and 30 min of reperfusion. Preconditioning (P1 or P2) significantly (P less than 0.0005) improved recovery of the rate-pressure product; percentage recoveries were 17.8 +/- 3.2 (n = 14), 59.9 +/- 5.5 (n = 6), and 46.4 +/- 4.7 (n = 8) for control, P1, and P2, respectively. Improved functional recovery of preconditioned hearts was associated with reduced end-diastolic pressure and improved myocardial perfusion. During the 40-min ischemic period, myocardial pH decreased from approximately 7.4 to 6.3 +/- 0.1 (n = 7) in the control hearts and to 6.7 +/- 0.1 (n = 7) in the preconditioned hearts (P less than 0.01). Also during the 40-min ischemic period, myocardial lactate (expressed as nmol/mg protein) increased to 146 +/- 11 (n = 7) and 101 +/- 12 (n = 8) in control and preconditioned hearts, respectively (P less than 0.02). The results demonstrate that a brief episode of ischemia can protect the isolated rat heart from a prolonged period of ischemia. This protection is associated with decreased tissue acidosis and anaerobic glycolysis during the sustained ischemic period.
ISSN:0002-9513
2163-5773
DOI:10.1152/ajpheart.1992.263.3.h887