Abstract:The hypothesis that oral supplementation with virgin coconut oil (Cocos nucifera L.) and exercise training would improve impaired baroreflex sensitivity (BRS) and reduce oxidative stress in spontaneously hypertensive rats (SHR) was tested. Adult male SHR and Wistar Kyoto rats (WKY) were divided into 5 groups: WKY + saline (n = 8); SHR + saline (n = 8); SHR + coconut oil (2 mL·day −1 , n = 8); SHR + trained (n = 8); and SHR + trained + coconut oil (n = 8). Mean arterial pressure (MAP) was recorded and BRS was tested using phenylephrine (8 g/kg, intravenous) and sodium nitroprusside (25 g·kg −1 , intravenous). Oxidative stress was measured using dihydroethidium in heart and aorta. SHR + saline, SHR + coconut oil, and SHR + trained group showed higher MAP compared with WKY + saline (175 ± 6, 148 ± 6, 147 ± 7 vs. 113 ± 2 mm Hg; p < 0.05). SHR + coconut oil, SHR + trained group, and SHR + trained + coconut oil groups presented lower MAP compared with SHR + saline group (148 ± 6, 147 ± 7, 134 ± 8 vs. 175 ± 6 mm Hg; p < 0.05). Coconut oil combined with exercise training improved BRS in SHR compared with SHR + saline group (−2.47 ± 0.3 vs. −1.39 ± 0.09 beats·min −1 ·mm Hg −1 ; p < 0.05). SHR + saline group showed higher superoxide levels when compared with WKY + saline (774 ± 31 vs. 634 ± 19 arbitrary units (AU), respectively; p < 0.05). SHR + trained + coconut oil group presented reduced oxidative stress compared with SHR + saline in heart (622 ± 16 vs. 774 ± 31 AU, p < 0.05). In aorta, coconut oil reduced oxidative stress in SHR compared with SHR + saline group (454 ± 33 vs. 689 ± 29 AU, p < 0.05). Oral supplementation with coconut oil combined with exercise training improved impaired BRS and reduced oxidative stress in SHR.Key words: virgin coconut oil, swimming, hypertension, baroreflex, antioxidant.
Résumé :On vérifie l'hypothèse selon laquelle la supplémentation per os en huile de coco (Cocos nucifera L.) vierge et l'entraînement physique atténuent le dérèglement de la sensibilité du baroréflexe (« BRS ») et diminuent le stress oxydatif chez des rats spontanément hypertendus (« SHR »). On répartit des rats mâles adultes SHR et Wistar Kyoto (« WKY ») en cinq groupes : WKY + saline (n = 8); SHR + saline (n = 8); SHR + huile de coco (2 mL·jour −1 , n = 8); SHR + entraînés (n = 8) et SHR + entraînés + huile de coco (n = 8). On enregistre la pression artérielle moyenne (« MAP ») et on évalue la BRS par l'administration de phényléphrine (8 g·kg −1 , intraveineux) et de nitroprussiate de sodium (25 g·kg −1 , intraveineux). On évalue le stress oxydatif par l'administration de dihydroéthidium dans le coeur et l'aorte. Les groupes SHR + saline, SHR + huile de coco et SHR + entraînés présentent une MAP plus élevée comparativement au groupe WKY + saline (175 ± 6, 148 ± 6, 147 ± 7 vs 113 ± 2 mm Hg, p < 0,05). Les groupes SHR + huile de coco, SHR + entraînés, SHR + entraînés + huile de coco présentent une MAP plus basse comparativement au groupe SHR + saline (148 ± 6, 147 ± 7, 134 ± 8 vs 175 ± 6 mm Hg, p < 0,05). L'hui...