The Effects of Hesperidin, on Cardiac Dysfunction of Experimental Type-I Diabetic Rats

ABSTRACT: Introduction & Objective: 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 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). Material & Methods: 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. Results: 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). Conclusion: These results show that hesperidin can improve diabetic cardiomyopathy in experimental diabetes mellitus

Effects of CGS 21680, a selective A(2A) adenosine receptor agonist, on cardiac output and vascular resistance in acute heart failure in the anaesthetized rat

1. The effects of CGS 21680, a selective A(2A) adenosine receptor agonist, on cardiac output, blood pressure, mean circulatory filling pressure (P(mcf)), arterial and venous resistances, heart rate and left ventricular end-diastolic pressure were assessed in rats with acute heart failure by means of coronary artery occlusion. 2. Animals (n=6 in each group) were divided into five groups: group I, sham-operated vehicle-treated (0.9% saline; 0.018 mL min(−1)); groups II-V, subject to coronary artery occlusion and treated with vehicle (0.9% saline; 0.018 ml min(−1)) and CGS 21680 (0.1, 0.3 and 1.0 μg kg(−1) min(−1)), respectively. Haemodynamic measurements were taken one hour after completion of surgery, ninety minutes after coronary artery occlusion (except in group I), and fifteen minutes after infusion of saline or CGS 21680. 3. Baseline haemodynamic measurements before occlusion were found not to differ significantly between the different groups of animals. However, after occlusion, cardiac output, rate of rise in left ventricular pressure (+dP/dt) and blood pressure were significantly reduced when compared to corresponding values in sham-operated animals. In addition, occlusion of the coronary artery resulted in a significant elevation in venous resistance, P(mcf) and left ventricular end-diastolic pressure as compared to corresponding values in sham-operated animals. 4. Infusion with CGS 21680 at the highest dose significantly reduced blood pressure, arterial resistance and left ventricular end-diastolic pressure when compared to occluded vehicle-treated animals (group II). Administration of CGS 21680 at the highest dose also significantly increased cardiac output (28%) and heart rate (10%) in comparison to occluded vehicle-treated animals. In addition, the highest dose of CGS 21680 significantly reduced P(mcf) (9%) and venous resistance (62%) in comparison to occluded vehicle-treated animals. Administration of CGS 21680 did not significantly affect +dP/dt when compared to occluded vehicle-treated animals. 5. The results from the present investigation indicate that occlusion of the coronary artery in rats results in a state of heart failure characterized by reduced arterial pressure and cardiac output, and increased venous resistance, P(mcf) and left ventricular end-diastolic pressure. Administration of CGS 21680 to animals with acute heart failure resulted in increased cardiac output which was due to reduced venous resistance, as well as increased heart rate

Right ventricular pressure elevated in one-kidney, one clip Goldblatt hypertensive rats

Both renal and respiratory diseases are common with high mortality rate around the world. This study was the first to compare effects of two kidneys, one clip (2K1C) and one-kidney, one clip (1K1C) Goldblatt hypertension on right ventricular pressure during normal condition and mechanical ventilation with hypoxia gas. Male Sprague–Dawley rats were subjected to control, 2K1C, or 1K1C groups. Twenty-eight days after the first surgery, animals were anesthetized, and femoral artery and vein, and right ventricle cannulated. Systemic arterial pressure and right ventricular systolic pressures (RVSP) were recorded during ventilation the animals with normoxic or hypoxic gas. RVSP in the 1K1C group was significantly more than the control and 2K1C groups during baseline conditions and ventilation the animals with hypoxic gas. Administration of antioxidant Trolox increased RVSP in the 1K1C and control groups compared with their baselines. Furthermore, there was no alteration in RVSP during hypoxia in the presence of Trolox. This study indicated that RVSP only increased after 28 days induction of 1K1C but not 2K1C model. In addition, it seems that the response to hypoxic gas and antioxidants in 1K1C is more than 2K1C. These data also suggest that effects of 1K1C may partially be related to reactive oxygen species (ROS) pathways

Haemodynamic effects of a selective adenosine A(2A) receptor agonist, CGS 21680, in chronic heart failure in anaesthetized rats

1. Recently we demonstrated that the administration of an A(2A) adenosine receptor agonist, CGS 21680, to anaesthetized rats with acute heart failure (1 h post-coronary artery ligation) resulted in an increase in cardiac output. In the present investigation, the effects of CGS 21680 on cardiac output, vascular resistance, heart rate, blood pressure and mean circulatory filling pressure (Pmcf) were investigated in anaesthetized rats with chronic heart failure (8 weeks post-coronary artery ligation). 2. Experiments were conducted in five groups (n=6) of animals: sham-operated vehicle-treated (0.9% NaCl; 0.037 mL kg(−1) min(−1)) animals in which the occluder was placed but not pulled to ligate the coronary artery; coronary artery-ligated vehicle-treated animals; and coronary artery-ligated CGS 21680-treated (0.1, 0.3 or 1.0 μg kg(−1) min(−1)) animals. 3. Baseline blood pressure, cardiac output and rate of rise in left ventricular pressure (+dP/dt) were significantly reduced in animals with coronary artery ligation when compared to sham-operated animals. Coronary artery ligation resulted in a significant increase in left ventricular end-diastolic pressure, Pmcf and venous resistance when compared to sham-operated animals. 4. Administration of CGS 21680 at 0.3 and 1.0 μg kg(−1) min(−1) significantly (n=6; P<0.05) increased cardiac output by 19±4% and 39±5%, and heart rate by 14±2% and 15±1%, respectively, when compared to vehicle treatment in coronary artery-ligated animals. Administration of CGS 21680 also significantly reduced blood pressure and arterial resistance when compared to coronary artery-ligated vehicle-treated animals. Infusion of CGS 21680 also significantly reduced venous resistance when compared to vehicle-treated coronary artery-ligated animals. 5. The results show that heart failure is characterized by reduced cardiac output, and increased left ventricular end-diastolic pressure, venous resistance and Pmcf. Acute treatment with CGS 21680 in animals with chronic heart failure decreased left ventricular end-diastolic pressure and increased cardiac output. This increase in cardiac output was the result of reduced arterial and venous resistances and increased heart rate