Mechanical properties of mesenteric arteries in diabetic rats: consequences of outward remodeling

Diabetes induces hemodynamic and biochemical changes that can influence mechanical properties of arteries. Structure and mechanics of mesenteric small arteries were investigated in rats with streptozotocin-induced diabetes (duration 7-9 wk). The external diameter of mesenteric artery branches was measured in control (n = 9) and diabetic (n = 7) Wistar Rp rats at baseline and during pressurization in situ (0-150 mmHg) under normal and passive smooth muscle conditions. Mean arterial pressure and mesenteric artery pressure were not significantly different. Baseline mesenteric artery diameter was larger in the diabetes-induced group (439 +/- 12 vs. 388 +/- 18 mu m, P < 0.05). Media cross-sectional area of arteries from diabetic rats was not significantly increased (0.0149 +/- 0.0015 vs. 0.0122 +/- 0.0007 mm(2)). Cross-sectional compliance was significantly increased in diabetic rats at intraluminal pressures ranging from 25 to 75 mmHg (P < 0.005), whereas cross-sectional distensibility was not modified. Wall tension and circumferential wall stress were increased in diabetes. These results indicate that mesenteric small arteries of diabetic rats display eutrophic outward remodeling associated with increased wall tension and circumferential wall stress.