Ischemic preconditioning attenuates acidosis and postischemic dysfunction in isolated rat heart

G. K. Asimakis, K. Inners-McBride, G. Medellin, V. R. Conti

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216 Scopus citations

Abstract

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 < 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 ~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 < 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 < 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.

Original languageEnglish (US)
Pages (from-to)H887-H894
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume263
Issue number3 32-3
StatePublished - Jan 1 1992

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Keywords

  • ischemic contracture
  • pH
  • reperfusion

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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