Impaired Elastic Properties of the Aorta in Fat-Fed, Streptozotocin-Treated Rats

BACKGROUND: Vascular complications associated with diabetes are the major cause for the increased morbidity and mortality in diabetic patients. However, the progression of vascular complications in diabetes is not well understood. We aimed to investigate the biomechanical and biochemical changes associated with vascular dysfunction in diabetic rats. METHODS: Male Wistar rats were randomly divided into two groups: normal control (n = 8) and fat-fed, streptozotocin-treated diabetic rats (n = 11). After 16 weeks, Peterson's modulus of elasticity (Ep) and cross-sectional distensibility (CD) were calculated and compared between the two groups. Aortas were harvested from rats for histopathological and electron-microscopic analysis. RESULTS: Collagenous fibers were scattered in the extracellular matrix and invaded the elastic lamina in the aortas of diabetic rats, suggesting a significant accumulation of collagen in diabetic vessels. Compared with normal rats, diabetic rats showed significantly reduced aortic distensibility (CD: 0.10 +/- 0.04 vs. 0.17 +/- 0.08 kPa(-1), p = 0.033) and an increased aortic stiffness index (Ep: 0.25 +/- 0.13 vs. 0.15 +/- 0.05 x 10(6) dyn/cm(2), p = 0.045). Ep was positively and CD negatively correlated with glucose and collagen in diabetic rats. CONCLUSIONS: In diabetic rats, elastic properties of the aorta are impaired, being closely related to hyperglycemia-induced vascular wall remodeling.