Cicogna et al Protein-calorie restriction in hypertrophy Arq Bras Cardiol volume 72, (nº 4), 1999 Effects of Protein-Calorie Restriction on Mechanical Function of Hypertrophied Cardiac Muscle Original Article

Abstract

Objective -To assess the effect of food restriction (FR) on hypertrophied cardiac muscle in spontaneously hypertensive rats (SHR). Methods -Isolated papillary muscle preparations of the left ventricle (LV) of 60-day-old SHR and of normo- . PCM can affect a series of organs and tissues. There is evidence in humans and especially in experimental animals that PCM can cause damage to the cardiovascular system. PCM can promote the following alterations: 1) clinical changes that vary from bradycardia to heart failure; 2) functional changes, such as reduction in cardiac output, in ventricular compliance, and in myocardial contractility; 3) biochemical changes, such as the activation of calciumdependent proteinase, reduction of the protein synthesis and of the RNA/DNA ratio, and an increase in DNA; and 4) morphological changes, such as dilation of the cardiac chambers, atrophy and/or degeneration of myocytes, interstitial and mitochondrial edema, and increase in colagen The spontaneously hypertensive rats (SHR) were developed as a genetic model of hypertension, which in many ways is similar to essential hypertension in man. The animals develop early left ventricular hypertrophy (LV), which is responsible for the maintenance of the normal cardiac function, despite the elevated systemic blood pressure (BP). Information in the literature about the influence of different types of nutritional deficiencies on the functional behavior of the hypertrophied muscle is scarce 7-9 . Yokota et al 7 observed that SHR fed a protein-deficient diet showed deterioration of LV function. Tabayashi et al 8 observed that dogs with LV hypertrophy that underwent chronic PCM had normal pump function and a reduced myocardial contractility. Olivetti et al 9 , studying SHR with nutritional anemia, observed LV dilation and dysfunction in those animals. Due to lack of information in the literature about the association between PCM and function of the hyper