Food restriction does not impair myocardial mechanics during the healing period of myocardial infarction in the rat

Abstract

Papillary muscle mechanics were studied in 4 groups of rats: control (C) noninfarcted (n = 9), C infarcted (n = 9), food-restricted (FR) noninfarcted (n = 8) and FR infarcted (n = 9). Food-restricted animals were fed with 50% of chow consumed by the C rats. Myocardial infarction (MI) was promoted 6 weeks after food restriction, and myocardial contraction and relaxation were studied 3 weeks thereafter. Interestingly, MI size was larger (P <.04) in C (50% +/- 8%) than in FR (40% +/- 10%) rats. Maximal developed tension, rate of tension rise and decay, resting tension, and time to 50% relaxation studied at calcium concentrations of 0.5, 1.0, 1.5, 2.0, and 2.5 mmol/L were essentially similar in the 4 groups. Infarcted and noninfarcted FR rats presented longer time to peak tension. These unprecedented data indicated that food restriction (1) seems to engender myocardial protection against ischemia/reperfusion injury and (2) does not affect myocardial mechanical function at the end of the healing period of MI. (c) 2005 Elsevier Inc. All rights reserved.