Comparative effects of Glibenclamide and Nigella sativa on aortic contractile and dilation response in diabetic rat

Seyed Mojtaba Mousavi1, Abbasali Abbasnezhad2*, Reza Mohebbati3, Mojtaba Kianmehr4, Mohammad Ghorbani5

1Department of Neuroscience, School of Advanced Technologies in Medicine, Tehran university of Medical Sciences, Tehran, Iran - 2Department of Physiology, Faculty of medicine, Gonabad 1University of Medical Sciences, Gonabad, Iran - 3Neurogenic Inflammation Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran - 4Department of medical Physic, Faculty of medicine, Gonabad University of Medical Sciences, Gonabad, Iran - 5Department of Hematology, Faculty of medicine, Gonabad University of Medical Sciences, Gonabad, Iran

Introduction: Diabetes is an important risk factor for cardiovascular events. The great percent of morbidity in patients with diabetes is due to endothelial dysfunction. The present study investigated the effects of Glibenclamide (GL) and hydroalcholic extract of Nigella sativa (NS) on isolated aortic contractile and dilation response in streptozotocin (STZ)-induced diabetic rat.

Materials and methods: Rats were divided into four experimental groups (control, untreated STZ-diabetic, and NS hydroalcholic extract or GL treated diabetic rats). Treated rats received NS extract (200 mg/kg) or GL (5 mg/kg) by gavage, daily for 6 weeks. Thoracic aortic rings were mounted in an organ bath system then contractile and dilatation responses induced by phenylephrine (PE), acetylcholine (ACh), potassium chloride (KCl) and sodium nitroprusside (SNP) were evaluated in different situations.

Results: Blood glucose levels in the group DE and GL at day 24 and 45 were significantly lower than diabetic group (P < 0.05, < 0.01). The lower concentrations of NS extract (DE 200) and GL significantly reduced the contractile responses to higher concentrations of PE (10-6 - 10-5 M) compared to diabetic group (P < 0.05 to P < 0.01).The relaxation response to Ach 10-8 M, was increased in DE 200 and GL groups than diabetic group (P < 0.05). The relaxation responses to Ach 10-7 - 10-5 M were significantly higher in both treated groups compared to diabetic group (P < 0.05 to P < 0.001).

Conclusion: The chronic administration of NS extract or GL has a significant hypoglycemic effect and improves aortic reactivity to vasoconstrictor and vasodilator agents in STZ-induced diabetic rats. No significant difference in hypoglycemic effect and improving of aortic reactivity was observed between NS extract and GL.