Oral supplementation with the rutin improves cardiovagal baroreflex sensitivity and vascular reactivity in hypertensive rats

Abstract

The hypothesis that oral supplementation with the flavonoid rutin improves baroreflex sensitivity and vascular reactivity in hypertensive (2-kidney-1-clip (2K1C)) rats was tested. Sixty-four rats were divided in 4 groups: sham + saline; sham + rutin; 2K1C + saline, and 2K1C + rutin. Six weeks after 2K1C surgery, the animals were treated with saline or rutin (40 mg·kg−1·day−1) by gavage for 7 days. Baroreflex sensitivity test using phenylephrine (8 μg·kg−1, iv) and sodium nitroprusside (25 μg·kg−1, iv), vascular reactivity, and thiobarbituric acid reactive substances assay were performed. Baroreflex sensitivity in hypertensive rats was impaired and compared with sham (−2.77 ± 0.15 vs. –1.53 ± 0.27 beats·min−1·mm Hg−1; n = 8; p < 0.05). Oral supplementation with rutin restored baroreflex sensitivity in 2K1C rats (−2.40 ± 0.24 vs. –2.77 ± 0.15 beats·min−1·mm Hg−1; n = 8; p > 0.05). Besides, hypertensive rats have greater contraction to phenylephrine (129.49% ± 4.46% vs. 99.50% ± 11.36%; n = 8; p < 0.05), which was restored by rutin (99.10% ± 1.77% vs. 99.50% ± 11.36%; n = 8; p > 0.05). Furthermore, vasorelaxation to acetylcholine was diminished in hypertensive rats (96.42% ± 2.80% vs. 119.35% ± 5.60%; n = 8; p < 0.05), which was also restored by rutin (117.55% ± 6.94% vs. 119.35% ± 5.60%; n = 8; p > 0.05). Finally, oxidative stress was greater in hypertensive rats (1.54 ± 0.12 vs. 0.53 ± 0.12 nmol MDA·mL−1; n = 8; p < 0.05) and rutin supplementation significantly decreased oxidative stress in those animals (0.70 ± 0.13 vs. 1.54 ± 0.12 nmol MDA·mL−1; n = 8; p < 0.05). We concluded that oral supplementation with rutin restores impaired baroreflex sensitivity and vascular reactivity in hypertensive rats by decreasing oxidative stress.