COMPARATIVE ASPECTS OF CARDIAC ULTRASTRUCTURE, MORPHOMETRY, AND ELECTROCARDIOGRAPHY OF HEARTS FROM RATS FED RESTRICTED DIETARY COPPER AND SELENIUM

Comparative cardiac ultrastructure, morphometry, and electro-cardiogra phy after dietary copper and selenium restriction were examined. Male weanling Long-Evans rats were fed diets that were either adequate in b oth copper and selenium (Cu+/Se+) or restricted in either Cu (Cu-) or Se (Se-) for 8 wk. At wk 8, electrocardiograms (ECG) and dP/dts were o btained and heart tissue was utilized for electron microscopy. Upon ex amination, Cu- rats were anemic, exhibited a greater heart: body weigh t ratio, and developed concentric hypertrophy characterized by an enha nced thickening of the left and right ventricular free walls, and inte rventricular septum. ECG recordings from lead aVF in the Cu- group sho wed a greater R wave amplitude in comparison to the Cu+/Se+ group. Se- rats recorded a greater left ventricular +dP/dt(max) than both the Cu +/Se+ and Cu- groups. Cardiac myofibril volume densities were decrease d in both Cu- and Se- rats in comparison to the Cu+/Se+ rats. In addit ion Cu- rats showed a greater mitochondria:myofibril ratio. Sarcomere contractile protein disarray was present in both the Cu- and Se- group s. Se- myocytes also showed evidence of edema and mitochondrial. fragm entation. The subcellular alterations suggest that similarities exist in the cardiac remodeling processes associated with topper and seleniu m restrictions.