The effect of chronic administration of sesamin was studied on aortic reactivity of streptozotocin diabetic
rats. Male diabetic rats received sesamin for 7 weeks after diabetes induction. Contractile responses to KCl
and phenylephrine and relaxation response to acetylcholine were obtained from aortic rings. Maximum
contractile response of endothelium-intact rings to phenylephrine was significantly lower in sesamintreated
diabetic rats relative to untreated diabetics and endothelium removal abolished this difference.
Meanwhile, endothelium-dependent relaxation to acetylcholine was significantly higher in sesamin-treated
diabetic rats as compared to diabetic ones and pretreatment of rings with nitric oxide synthase inhibitor
N(G)-nitro-L-arginine methyl ester significantly attenuated the observed response. Two-month diabetes
also resulted in an elevation of malondialdehyde and decreased superoxide dismutase activity and sesamin
treatment significantly improved these changes. Therefore, chronic treatment of diabetic rats with sesamin
could prevent some abnormal changes in vascular reactivity in diabetic rats through nitric oxide and via
attenuation of oxidative stress and tissue integrity of endothelium is necessary for its beneficial effect