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Accumulation of lipid in muscular arteries of short-term diabetic rats. An electron microscope study
Abstract:
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.
Insights
Acute diabetes in rats causes lipid accumulation in muscular arteries. High non-esterified fatty acids in plasma correlate with these arterial lipid deposits, suggesting a direct link.
Area of Science:
- Vascular Biology
- Metabolic Disorders
- Histopathology
Background:
- Diabetes mellitus is a metabolic disorder characterized by hyperglycemia.
- Vascular complications are a major concern in diabetes.
- Early detection of arterial changes in diabetes is crucial.
Purpose of the Study:
- To investigate lipid accumulation in arterial smooth muscle cells of diabetic rats.
- To identify the type of lipid deposited and its correlation with metabolic parameters.
- To explore the role of plasma non-esterified fatty acids in arterial lipid deposition during acute diabetes.
Main Methods:
- Electron microscopy was used to examine arterial tissue from streptozotocin-induced diabetic rats and controls.
- Histochemical analysis identified the deposited lipid as triacylglycerol.
- Plasma glucose, non-esterified fatty acids, and insulin levels were measured.
Main Results:
- Lipid deposits were observed in the muscular arteries of diabetic rats but not in control rats or in the elastic arteries of either group.
- Diabetic rats with arterial lipid deposits showed significantly higher plasma glucose and non-esterified fatty acids, and lower plasma insulin levels.
- The extent of arterial lipid accumulation correlated positively with plasma non-esterified fatty acid concentrations.
Conclusions:
- Acute diabetes induces triacylglycerol accumulation in the smooth muscle cells of muscular arteries.
- Elevated plasma non-esterified fatty acids are strongly associated with arterial lipid deposition in diabetic rats.
- These findings suggest that high non-esterified fatty acid levels contribute to early vascular changes in diabetes.