Effects of lifelong ethanol consumption on the ultrastructure and lipopigmentation of rat heart.

The myocardial interactions of ageing and lifelong ethanol ingestion were studied in the ethanol-preferring AA (Alko Alcohol) line of rats. Samples of the left ventricle from young control rats (3-month), old control rats (30-month) and rats exposed to ethanol from 3 to 30 months of age, were studied in terms of myocardial ultrastructure and lipopigmentation. Electron microscopic morphometry showed an age-related increase in the volumetric densities of lipofuscin and unspecified sarcoplasm, while the proportions of mitochondria, myofibrils and tubular structures remained unaltered in the left ventricular myocardium. Lifelong ethanol exposure increased the proportion of sarcoplasmic reticulum and transverse tubules, apparently due to dilation of the tubular structures. Mitochondria were significantly larger in the ethanol-exposed rats compared to the control rats of the same age, while the volumetric proportion of mitochondria tended to decrease in the ethanol-exposed group. Fluorescence microscopic image analysis showed that myocardial lipopigmentation (proportion of myocardial area covered by autofluorescent lipopigments) was about two-fold in the old ethanol-exposed rats compared to the old control rats, and 13-fold compared to the young controls. It is concluded that ageing and chronic ethanol ingestion produce rather different patterns of alteration in myocardial ultrastructure, which does not support the concept of ethanol-induced accelerated ageing. The enhancement of myocardial lipofuscin accumulation is thought to reflect chronic oxidative stress in the hearts exposed to ethanol.