Accumulation of lipid in muscular arteries of short-term diabetic rats. An electron microscope study.

Lipid accumulation in muscular (pulmonary, coronary and tibial) arteries and elastic (aorta and pulmonary) arteries of streptozotocin diabetic (65 mg/kg) rats was studied with an electron microscope. Arterial tissue specimens taken 4 days after the induction of diabetes showed lipid deposits in smooth muscle cells in the muscular arteries of 9 out of 24 diabetic rats, but in none of the 17 control rats. Histochemically the lipid was identified as triacylglycerol. Lipid accumulation was not seen in the elastic arteries of either diabetic or control rat. The diabetic animals with lipid deposits had slightly but significantly higher plasma glucose concentrations (p < 0.02), higher non-esterified fatty acids levels (p < 0.01), and lower concentrations of plasma insulin (p < 0.02) than those without arterial deposits. The amount of lipid deposited in the arteries was closely related to the plasma non-esterified fatty acid level, which was in the ranges 0.8-1.1 mmol/l in diabetic rats without deposits, and 1.1-2.4 mmol/l in those with deposits. The findings suggest that lipid accumulations in smooth muscle cells of muscular arteries during acute diabetes could result from the high plasma non-esterified fatty acid concentrations.