Ethanol feeding produces deficiencies in left ventricle total RNA, total DNA and mitochondrial ribosomal RNA

Chronic alcoholism causes a variety of ultrastructural, biochemical and functional alterations in the myocardium, but the underlying mechanisms are not well understood. Molecular changes that developed in the left ventricles of rats fed for 1 to 24 weeks on liquid diets containing ethanol as 36% of total calories were analyzed. Total tissue RNA and DNA were chemically extracted and measured by spectroscopic methods; mitochondrial DNA and mitochondrially-coded ribosomal RNA were measured at the 12s rRNA region by a quantitative polymerase chain reaction method; mitochondrial protein and enzyme activities were assayed. Ethanol-fed rats had 83.9 +/- 2.9% (mean +/- S.E.M.) as much DNA/g tissue and 74.7 +/- 3.9% as much total left ventricle DNA as pair-fed controls (P < 0.001). The alcoholics had 71.4 +/- 1.7% as much RNA/g tissue and 64.4 +/- 2.7% as much total left ventricle RNA as controls (P < 0.001). Mitochondrially-coded 12s rRNA was a lower proportion of total left ventricle RNA in all of the alcoholics; it was only 59.9 +/- 4.6% of control values (P < 0.001). Total left ventricle 12s rRNA was < 40% of normal. There was little or no change in mitochondrial DNA levels measured at the 12s location. Mitochondrial cytochrome contents were reduced 26-38% in the ethanol-fed rats, but only after 24 weeks. This study shows that experimental alcoholism produces rapid and sustained decreases in left ventricle total RNA and DNA and mitochondrial ribosomal RNA. The observed effects would be expected to have a major impact on left ventricle structural integrity and functional capacity.