Biochemical and morphological studies of skeletal muscle in experimental chronic alcoholic myopathy

Abstract

Experimental alcoholic myopathy was induced in rats by a combination of prolonged alcohol intake (mean 15.3 g ethanol/kg/day for up to 10 weeks) and a short fast. In view of literature evidence for impairment of both glycolytic and oxidative metabolism in alcoholic myopathy, we combined histological and histochemical observations with biochemical studies comprising assay of all glycolytic enzymes and measurement of respiration rates and cytochrome content in isolated intact mitochondria. The predominant histological finding was Type IIb fibre atrophy, while levels of the glycolytic enzymes aldolase, pyruvate kinase and lactate dehydrogenase were significantly depressed. Evidence of rhabdomyolysis was seen in a minority of animals. Mean mitochondrial respiratory rates were significantly lower with the Site I substrate glutamate in alcohol-treated animals. It is postulated that chronic alcoholic myopathy is associated with glycolytic deficiency and that acute rhabdomyolysis may arise from a superimposed mitochondrial failure, resulting in a severe energy crisis in muscle.