Effect of Concomitant Administration of a-tocopherol and ACEI on Cardiovascular Performance and Nucleic Acid Changes in DOCA Hypertensive Rats

Abstract

Background: Evidence for cardiovascular oxidative stress in animals with hypertension has been accumulated. Antioxidant agents have been used to treat endothelial dysfunction and arterial hypertension. Aim: The aim of present study is to elucidate the effect of concomitant administration of α-tocopherol (antioxidant) and angiotensin converting enzyme inhibitor (ACEI; anti-hyptertensive) on cardiac smooth muscle DNA and RNA changes in DOCA induced hypertension in rats. Methods: 48 male Sprague-Dawley rats were used in this study and were divided into 6 groups (n=8): C control rats; CE control rats received α-tocopherol (60 mg/kg) intragastrically (IG); DOCA rats were made hypertensive by SC injection of DOCA (50 mg/kg once weekly for 4 weeks); DOCA+E; DOCA hypertensive rats received α-tocopherol (60 mg/kg) IG; DOCA+ACEI; DOCA hypertensive rats received ACEI (captopril; 15 mg/kg) IG; and DOCA+E+ACEI; DOCA hypertensive rats received both α-tocopherol and captopril in the same doses as DOCA+E and DOCA+ACEI groups respectively. All IG treatments were given to the animals 6 days weekly for 6 weeks. At the end of experimental protocol, systolic blood pressure (MSP), renal vascular flow velocity (RFV), renal vascular resistance (RVR), myocardial contractility (MC) and heart rate (HR) were measured in rats of all groups. Also, serum sodium (Na + ), potassium (K + ) and total plasma antioxidant capacity (TOC) were measured. DNA and RNA analysis were done for the myocardial tissue homogenate. Results: While DOCA administration in rats produced significant increase in serum Na + , MSP, RVR, and RNA levels; it reduced significantly serum K + , TOC, MC and DNA levels compared with the control group. Concomitant administration of both α-tocopherol and ACEI resulted in significant reduction of serum Na + ,