Morphology and enzyme activities of the retinal capillaries in mice with the obese-hyperglycaemic syndrome (gene symbol ob).

The retinal capillary bed from 67 obese-hyperglycaemic mice and 64 lean litter mates was isolated by trypsin digestion and investigated with respect to structure and enzyme activities. There was no significant difference in the ratio between numbers of endothelial and mural cells. The capillary walls did not show any obvious structural differences and microaneurysms were not observed. The retinal vessels from the obese-hyperglycaemic mice, however, displayed significantly higher activities of the enzymes hydroxyacyl-CoA-dehydrogenase, asparate aminotransferase (ASAT) and adenylate kinase than their lean litter mates. The activities of glutathione reductase, glucose-6-phosphate dehydrogenase (G-6-PDH) and phosphofructokinase were similar in the two experimental groups. It is suggested that the present data reflect early metabolic disturbances related to diabetic retinopathy.