Original Article The Role of Adrenergic and Angiotensinergic Systems in Vascular Effect of Alcoholic of Extract Trigonella foenum-graecum Seed in Diabetic Rats

Considering the anti-diabetic potential of Trigonella foenum-graecum (TFG) and its beneficial effect on aortic reactivity of diabetic rats, this study was conducted to evaluate the effect of its alcoholic seed extract on aortic reactivity and also figure out mechanisms including the role of adrenergic and angiotensinergic systems in streptozotocin-diabetic rats. Male Wistar rats were divided into control, extract-treated control, diabetic, and extract-treated diabetic groups. Diabetes was induced by a single IP injection of streptozotocin (STZ; 60 mg/kg). Treatment groups received TFG extract (200 mg/kg; IP) every other day for 1 month. Contractile response of thoracic aorta to KCl and noradrenaline (NA) was then determined. For determination of the involvement of adrenergic and angiotensinergic systems, rings were incubated before the experiments with prazocin, propranolol, and/ or captopril and then NA- and angiotensin I (Ag-I)-induced contractions were recorded. Diabetic state significantly increased maximum contractile response to KCl and NA (p < 0.01-0.005) comparing to control groups and treatment with TFG extract in diabetic group significantly improved these changes comparing to untreated diabetic group (p < 0.05-p < 0.01). On the other hand, pretreatment of prazosin and propranolol caused a significant reduction in contractile response of all groups (p < 0.05-0.001) meanwhile was no significant difference among the groups. In addition, pre-incubation with captopril caused a significant reduction in contractile response of TFG-treated diabetic group comparing untreated diabetic group (p < 0.05). Finally we concluded that alcoholic seed extract of TFG could improve some functional indices of the vascular system in diabetic state and angiotensinergic system is partly involved in this response