Direct vasodilatory activity of red wine in streptozotocin-diabetic rats

Introduction: Red wine is antioxidant and direct, endothelium-dependent vasodilator. Diabetes mellitus (DM) alters vascular responsiveness as a result of oxidative stress and chronic high blood glucose. The present study was designed to examine red wine vasodilatory activity in the rats with streptozotocin-induced type 1 DM. Materials and methods: DM was induced with intaperitoneal injection of streptozotocin (55 mg/kg) to male Sprague-Dawley rats. The DM rats were treated once a week with long-lasting insulin therapy. 14 months after induction of DM, control (C, non- diabetic, 14 months old) and diabetic rats were anesthetized and thoracic aortas excised (N=15 per group). The isolated aortic rings were precontracted with noradrenaline (10-7 M) and randomly exposed to red wine (“Zlatan Plavac” 2008, Plenkovic), acetylcholine or sodium nitroprusside. Vasodilation was measured, dose- response curves analyzed. Results: Red wine induced vasodilation in control and diabetic aorta. DM did not significantly affect maximal vasodilatory activity (Emax) of red wine (Emax 63, 75±5, 01% and 55, 75±5, 68% for C and DM, respectively). However, 50% effective concentration, EC50 of wine was increased in diabetic aorta (EC50 of 2, 01‰ (95% CI of 1, 68- 2, 41‰)) in comparison to control aorta (EC50 of 1, 06‰ (95% CI of 0, 87-1, 28‰)). Furthermore, the vasodilatory response to acetylcholine was significantly decreased in diabetic compared to the control aorta, as indicated by decreased Emax and EC50. No differences between diabetic and control aortas were observed in the vasodilatory response to sodium nitroprusside. Conclusion: Acetylcholine vasodilation was decreased in diabetic rats. DM also impaired red wine vasodilation potency, but did not affect its effectiveness.