Chronic heart failure (CHF) results in central and peripheral derangements that ultimately reduce skeletal muscle O2 delivery and impair exercise tolerance. Dietary nitrate (NO3-) supplementation improves skeletal muscle vascular function and improves tolerance to exercise. We tested the hypothesis that NO3- supplementation would elevate exercising skeletal muscle blood flow (BF) and vascular conductance (VC) in CHF rats. Myocardial infarction (MI) was induced (coronary artery ligation) in young-adult male rats. After 21-days of recovery, rats randomly received 5 days of NO3- rich beetroot juice (CHF+BR, n=10) or a placebo (CHF, n=10). Mean arterial pressure (MAP, carotid artery catheter) and skeletal muscle BF (radiolabeled microspheres) was measured during treadmill exercise (20 m/min, 5% grade). CHF-induced dysfunction (MI size, CHF: 29 ± 3, CHF+BR: 33 ± 4%, LVEDP, CHF: 18 ± 2, CHF+BR: 18 ± 2 mmHg) and exercising MAP (CHF: 131 ± 3, CHF +BR: 128 ± 4 mmHg) were not different (p>0.05) between groups. Total exercising hindlimb skeletal muscle BF (CHF: 95 ± 5, CHF+BR: 116 ± 9 ml/min/100g) and VC (CHF: 0.75 ± 0.05, CHF+BR: 0.90 ± 0.05) were 22% and 20% greater in BR supplemented rats, respectively (p<0.05). During exercise BF in 9 and VC in 10 hindlimb muscles and muscle portions were significantly greater in the CHF+BR group. These results provide strong evidence that dietary NO3- supplementation improves skeletal muscle vascular function during exercise in rats with CHF and thus supports the use of BR as a novel therapeutic modality for the treatment of CHF.
- blood flow
- myocardial infarction
- left ventricular end diastolic pressure
- Copyright © 2016, Journal of Applied Physiology