Beneficial effects of angiotensin (1–7) in diabetic rats with cardiomyopathy

Abstract

Objective: This study was designed to investigate the effect of angiotensin (1–7), a Mas receptor agonist, and A-779, a Mas receptor antagonist, in rats with diabetic cardiomyopathy (DC). Methods: Rats treated with a single injection of streptozotocin (50 mg/kg, intraperitoneal), developed DC after 8 weeks. The extent of DC was assessed by measuring the left ventricular weight/body weight (LVW/BW) ratio, absolute LVW, left ventricular developed pressure (LVDP), maximum change in left ventricular pressure over time (dp/dtmax), minimum change in left ventricular pressure over time (dp/dtmin), left ventricular (LV) protein content, LV collagen content, lipid profile, and serum nitrite/nitrate concentration. Test drug treatment was given from week 4 to week 8. Results: Angiotensin (1–7) treatment attenuated DC by significantly increasing LVDP, dp/dtmax, dp/dtmin, serum nitrite/nitrate concentration and significantly decreasing the LVW/BW ratio and LV collagen content. For the first time, this study has documented that endogenous angiotensin (1–7) regulates lipid profile in rats, and that treatment with angiotensin (1–7) significantly attenuates diabetes-induced changes in lipid profile. However, LV protein content and absolute LVW remain unaffected after treatment. Conclusion: Angiotensin (1–7) significantly attenuates DC in rats because of vasodilatory, antiproliferative and anifibrotic properties but also because of a significant decrease in dyslipidemia, the major culprit for cardiac dysfunctions in diabetes. © 2011, SAGE Publications. All rights reserved.