[ effect of tribulus terrestris on thoracic aorta contractile response in diabetic rats]

ABSTRACT

Considering the higher incidence of cardiovascular disorders in diabetes mellitus and some evidence on antioxidant and antidiabetic potential of Tribulus terrestris [TT], this study was conducted to evaluate the beneficial effect of 6-week oral administration of TT on contractile reactivity of isolated thoracic aorta in diabetic rats. Female Wistar rats were divided into control, TT-treated control, diabetic, glibenclamide-treated, and TT-treated diabetic groups. For induction of diabetes, streptozotcin [STZ] was administered [60 mg/Kg]. Meanwhile, TT-treated groups received TT-mixed with standard pelleted food at a weight ratio of 6.25% for 6 weeks. Serum glucose level was measured at weeks 3 and 6. Finally, contractile reactivity of thoracic aortic rings to KCl and phenylephrine [PE] was determined. Serum glucose level at weeks 3 and 6 showed a significant decrease in TT-treated diabetic group [P<0.01 and P<0.005 respectively] compared to diabetics. In addition, TT-treated diabetic group showed a significant 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 no significant difference between control and TT-treated control groups regarding their contractile reactivity to KCl and PE. Oral administration of TT for 6 weeks could exert a hypoglycemic effect and also attenuates the contractile responsiveness of the vascular system and this may prevent the development of hypertension in diabetic rats