effect of hydroalcoholic extract of olive leaves on blood pressure in rat model of two-kidney, one-clip goldblatt hypertension

In Iran's traditional medicine, the leaves of olive tree are of value for the treatment of hypertension. This study was designed to examine the effects of hydroalcoholic extract of olive leaves in rat model of two-kidney, one-clip hypertension and to further explore whether its hypotensive activity was mediated by enhancing the basal release of endothelium-derived nitric oxide. Animals were divided into two main groups including sham-operated and renal artery-clipped ones. The latter was further divided into 5 groups of untreated rats, vehicle-treated rats, which received daily oral administrations of one ml distilled water, and extract-treated rats receiving olive leaves extract at 50, 150 or 500 mg/kg in the same volume of vehicle starting the next day after the operation. Four weeks later, mean blood pressure and heart rate were measured under anesthesia before and after the administration of NG-nitro-L-arginine methyl ester [L-NAME]. Mean arterial pressures, and right kidney and heart weights of untreated and vehicle-treated renal artery-clipped rats were significantly higher but left kidney weights were significantly lower than those of shamoperated animals. However, there was no significant difference between the heart rates of these groups. Compared to vehicle-treated renal artery-clipped rats, treatment with hydroalcoholic extracts of olive leaves at 50, 150 or 500 mg/kg/day was associated with significantly lower mean arterial pressure, right kidney and heart weights but did not affect heart rate or left kidney weights. The intravenous administration of L-NAME resulted in a significant increase in mean arterial pressure in sham-operated and extract-treated rats whereas there was no change in renal artery clipped or vehicle-treated groups. The findings of the study show that hydroalcoholic extract of olive leaves prevents the clipinduced increase in mean arterial pressure, which might be partly mediated by enhancing the basal release of nitric oxide

[ effect of hesperidin, on cardiac dysfunction of experimental type-I diabetic rats]

Flavonoids are polyphenolic compounds, which are considered as antioxidants due to their ability to scavenge free radicals and inhibit enzymes in oxygen-reduction pathways. Various studies have shown that these products reduce the cardiovascular disease mortalities. Heart failure is one of the main cause of mortality in diabetic patients. It is believed that diabetes has deleterious cardiomyopathic effects, which would lead to heart failure. Several evidences indicate that oxidative stress is an important factor in the pathogenesis of diabetic complications, including cardiomyopathy. The objective of the present study was to examine the effects of hesperidin on cardiac function parameters in experimental diabetes mellitus type 1 [DM1]. Diabetes mellitus was induced in rats by single intraperitoneal injections of streptozotocin [60mg/kg]. diabetic rats were given oral Hesperidin [500 mg/kg] for two months. Afterwards, the animals' hearts were used to study left ventricular systolic pressure [LVSP], rate of rise [+dP/dT] and rate of decrease [-dP/dT] of left ventricular pressure, using Langendorff isolated heart apparatus. Diabetes significantly reduced the LVSP, +dP/dT and -dP/dT compared to the control group p<0.05]. Hesperidin significantly improved all measured parameters in diabetic animals [p<0.05]. These results show that hesperidin can improve diabetic cardiomyopathy in experimental diabetes mellitus

Improvement of endothelium-dependent relaxation in aorta of rat models type 1 and 2 diabetes by hespiridin

Vascular disease is the principal cause of morbidity and mortality in patients with diabetes. A considerable body of evidence implicates oxidative stress as an important pathogenic factor of diabetic vasculopathies. In the present study, the effect of hesperidin, a flavanone glycoside with antioxidant activity, is studied in endothelium-dependent relaxation of the rat aorta in experimental diabetes mellitus type 1 [DM1] and type 2 [DM2]. Single dose intraperitoneal injection of streptozocin [60mg/kg] and subcutaneous daily injection of dexamethasone [10mg/kg for one month] were used to induce DM1 and DM2, respectively. Hesperidin [500mg/kg] was administered orally for two months in DM1 and one month in DM2. The effect of acetylcholine [Ach] on phenyl ephrine [PE] induced. PE contracted aorta was then studied and the EC50 and maximal relaxant effect of Ach were calculated and compared in the two groups. In the experimental DM1, hesperidin restored endothelium-dependent relaxation near to those of normal animals. Its effect on experimental DM2 consisted of a significant reduction of EC50 value of Ach compared to those of diabetic animals. It also showed a great but non-significant effect [P = 0.07] on Ach-induced maximum relaxation compared to DM2 untreated animals. These results show that hesperidin can improve vascular endothelial dysfunction in experimental diabetes mellitus

Chronology of blood pressure changes in renal hypertension induced by solid plexiglass clips in the rat

The objective of this study was to determine the chronology of changes in blood pressure in renal hypertension induced by solid plexiglass clips in rats. Saw blades with the thickness of 0.21-0.22 mm were used to make clips sized 4 x 2 x 2 mm from a piece of 2-mm thick plexiglass. Rats were subjected to sham-operation or left renal arterial clipping, and 1, 2, 3 and 4 weeks later blood pressure, and heart and kidneys weights were determined. Relative to those of sham-operated rats, mean blood pressure of left renal artery-clipped rats were significantly higher at week 1 through 4 after clipping. Left renal artery clipping was also associated with significant increases in heart and right kidney weights and significant decrease in left kidney weight. The findings suggest that clipping of left renal artery using solid plexiglass clips resulted in changes in blood pressure, heart and left and right kidneys weights similar to reported changes in hypertension induced by silver clips

Pre-ischemic treatment of pentoxifylline reduces infarct volumes in transient focal cerebral ischemia in the rat

Pentoxifylline [PTX] is used in human for intermittent claudication and cerebral vascular disorders including cerebrovascular dementia. It also inhibits the synthesis of tumor necrosis factor-