Elevated activity of several antioxidant enzymes in neuromuscular diseases. A histochemical and biochemical study.

In the present study the activity of glucose-6-phosphate dehydrogenase, phosphogluconate dehydrogenase, glutathione peroxidase, glutathione reductase, superoxide dismutase and catalase was measured in dissected specimens from muscle biopsies of patients with various neuromuscular diseases and from controls. The biopsy specimens investigated were selected by means of histological and enzyme histochemical staining methods. Specimens were used which contained muscle fibres with a high or low activity of glucose-6-phosphate dehydrogenase and phosphogluconate dehydrogenase and which were free from inflammatory infiltrates. A rise in activity of glucose-6-phosphate dehydrogenase in pathologically changed muscle fibres was always found to be coupled with a significant rise in activity of phosphogluconate dehydrogenase, glutathione peroxidase and glutathione reductase. In these muscle fibres the activity of superoxide dismutase and catalase was not significantly changed. On the basis of the histochemical and biochemical findings it is concluded that the application of the histochemical method for the demonstration of glucose-6-phosphate dehydrogenase activity can be highly recommended for the study of antioxidant enzymes in skeletal muscles with neuromuscular diseases.