(715.23) Role of beetroots in oxidative stress and vascular relaxation in ovariectomized rats

Poster Board Number: E100

Hui Di Wang (Brock University), David Nguyen (Brock University), Arlinda Deng (Brock University), Amanda Longo (Brock University), Rebecca MacPherson (Brock University), Wendy Ward (Brock University)

The onset of hypertension in women is known to peak dramatically after menopause, partly due to decreased estrogen levels. It is well known that postmenopausal estrogen therapy can cause many adverse effects, and there is growing interest in using dietary products as potential treatment options. Dietary nitrates in beetroot may raise blood nitric oxide levels. We tested the hypothesis that beetroot can improve the oxidative stress and vascular relaxation responses in a model of an ovariectomized rodent.

Female ovariectomized Sprague-Dawley rats were divided into four treatment groups: beetroot juice (nitrate content 18.75mg), nitroglycerin (0.2 mg/kg), estradiol replacement (1.5mg) or no treatment for 12 weeks (n=4 per group). The isometric contractile activities were measured in isolated aortic rings mounted in tissue baths. Phenylephrine (10-6 M) was used to precontract the aortic rings. The contractile activities to various concentrations of acetylcholine and sodium nitroprusside were evaluated. The superoxide concentration was measured using chemiluminescence.

The beetroot treatment significantly reduced superoxide production (Plt;0.05). However, it did not affect acetylcholine or sodium nitroprusside-induced vascular relaxation at any of the concentrations used in the experiments (Pgt;0.05). There were no significant differences in acetylcholine-induced vascular relaxation curves among the different treatment groups (Pgt;0.05). In conclusion, these experiments indicate that dietary beetroot does not improve acetylcholine-mediated vascular relaxation while decreasing oxidative stress, contrary to expectations.

We would acknowledge the Natural Sciences and Engineering Research Council, which gave funding to Dr. Ward and Brocks BUFA grant for financial support.