The Effect of Flavonoid Naringenin on Contractile Response of Thoracic Aorta Isolated from Diabetic Rats

Considering increasing incidence of cardiovascular disorders in diabetes mellitus and some evidence on antioxidant and antidiabetic potentials of naringenin, this study was conducted to evaluate the beneficial effects of 6-week administration of naringenin on contractile reactivity of isolated thoracic aorta in diabetic rats. Male Wistar rats were divided into control, naringenin-treated control, diabetic and glibenclamide-treated, and naringenin-treated diabetic groups. For induction of diabetes, streptozotcin (STZ) was administered (60 mg/Kg). Naringenin (10 mg/kg) was administered i.p. one week after diabetes induction in every other day intervals for 6 weeks. Serum glucose level was measured before naringenin administration and at 6th week. Finally, contractile reactivity of thoracic aortic rings to KCl and phenylephrine (PE) was cumulatively determined. Serum glucose level at week 6 showed a significant decrease in naringenin-treated diabetic group compared to diabetics (P<0.01). In addition, naringenin-treated diabetic group showed a significantly lower contraction to PE (P<0.05) as compared to diabetic group and such significant reduction was also observed for KCl (P<0.05). Meanwhile, there was also a significant difference between control and naringenin-treated control groups regarding their contractile reactivity to PE (P<0.05). Subchronic administration of naringenin for 6 weeks could exert an anti-hyperglycemic effect and lowers contractile responsiveness of thoracic aorta rings to KCl and phenylephrine.