[Protein-energy malnutrition and hypobaric stress effects on ultrastructure of the heart muscle in rats].

A model that simulated nutritional and hypoxic stress is discussed. Wistar male adult rats were used in four groups: A1, A2, B1 and B2. A1 and A2 groups were fed with a diet whose composition was: 16% protein, 43% carbohydrate, and 6% lipids. Group B1 and B2 received the same type of diet but was restricted to 70% the amount consumed by groups A1 and A2. All groups were fed for 15 days. After these 15 days, the half of both groups were introduced into an hypobaric chamber simulating an altitude of 3,500 m for two hours. Pieces of the rats hearts were used for biochemical and ultrastructural studies. In group B a dear decrease in the body and the heart weight was observed. Also a decrement of the heart proteins concentration was noticed. On the contrary the mitochondrial proteins increased. These biochemical changes correlate with the ultrastructural changes observed in the same group in which a decrease of the myofibrilles and abnormal configurations of the mitochondria were found. The undemourishment and the hypobaric stress produced an evident alteration in the ultrastructure of the heart.