1978 Volume 21 Issue 3 Pages 219-226
It has been suggested that insulin may play an important role in the pathogenesis of atherosclerosis. Since the discovery of insulin in 1921, cardiovascular death in diabetic patients has increased and it is important to investigate the effect of insulin on the arterial wall. Eighty male Wistar rats, weighing 200 g, were divided into four groups-N group: control, A group: alloxanized-diabetic, Al group: alloxanized-diabetic treated with insulin, and I group: insulin treated. After 3 months, the rat aortae were removed and subjected to analysis for procoagulant activity, histological changes and lipid content. Procoagulant activities were determined by the method of recalcification time and the prothrombin two stage method. Total lipids were isolated and purified by a modification of the method of Folch and separated into esterified cholesterol (CE), free fatty acid (FFA), triglyceride (TG), free cholesterol (CH) and phospholipid (PL) fractions by thin layer chromatography.
The procoagulant activity of aortic extracts from the I group was markedly increased when compared to that in the other groups.
Lipid analysis of the aortic extracts revealed an increase in CE and decrease in FFA and PL in the I and Al groups.
Histological examinations revealed intimal and medial proliferation and most striking lipid droplets in the intimal and medial regions in the I group. The AI and A groups showed medial degeneration and slight lipid deposition in the same region as the I group.
These facts appear to suggest a role for excessive insulin in atherogenesis.