Cardiac muscle’s mitochondrial dysfunction in hypercholesterolemic rabbits

Abstract

Cardiovascular diseases are often associated with energy deficit and in many cases this is also accompanied by lipid disorders such as hyperlipidemias and obesity. The aim of the study was to check mitochondrial oxidative capacity in the course of twelve weeks atherogenic hypercholesterolic diet. Thirty five Chinchilla rabbits, male, were randomized to one of two groups a control group (A, n=17) received (per os) physiological saline experimental group (B, n=18) received atherogenic 2% hypercholesterolemic diet. Isolation of the mitochondrial fraction of the heart was done by the method of Tyler. The oxygen consumption rate was studied in different respiration phases: as basal, unstimulated (V4) and as ADP-stimulated (V3) and expressed as indices: respiratory control ratio (RCR) and ADP/O. Hypercholesterolemic atherogenic diet induced profound perturbations in mitochondrial energy metabolism and oxidative capacity. Basal oxygen consumption rate without ADP (V4) and the maximal ADP-stimulated respiration rate (V3) showed a marked reduction (quantitative changes); sensibility of mitochondria to ADP (ADP/O) was also reduced (qualitative change) in rabbits treated by atherogenic diet (group B) compared to controls (group A). Respiratory control ratio was not significantly different among the groups. These results indicate that hypercholesterolemic atherogenic diet impairs mitochondrial oxidative capacity without affecting coupling of oxidative and phosphorilative processes.