Effect of Dietary Docosahexaenoic Acid Supplementation on the Participation of Vasodilator Factors in Aorta from Orchidectomized Rats

Abstract

Benefits of n-3 polyunsaturated fatty acids (PUFAs) against cardiovascular diseases have been reported. Vascular tone regulation is largely mediated by endothelial factors whose release is modulated by sex hormones. Since the incidence of cardiovascular pathologies has been correlated with decreased levels of sex hormones, the aim of this study was to analyze whether a diet supplemented with the specific PUFA docosahexaenoic acid (DHA) could prevent vascular changes induced by an impaired gonadal function. For this purpose, control and orchidectomized rats were fed with a standard diet supplemented with 5% (w/w) sunflower oil or with 3% (w/w) sunflower oil plus 2% (w/w) DHA. The lipid profile, the blood pressure, the production of prostanoids and nitric oxide (NO), and the redox status of biological samples from control and orchidectomized rats, fed control or DHA-supplemented diet, were analyzed. The vasodilator response and the contribution of NO, prostanoids and hyperpolarizing mechanisms were also studied. The results showed that orchidectomy negatively affected the lipid profile, increased the production of prostanoids and reactive oxygen species (ROS), and decreased NO production and the antioxidant capacity, as well as the participation of hyperpolarizing mechanisms in the vasodilator responses. The DHA-supplemented diet of the orchidectomized rats decreased the release of prostanoids and ROS, while increasing NO production and the antioxidant capacity, and it also improved the lipid profile. Additionally, it restored the participation of hyperpolarizing mechanisms by activating potassium. Since the modifications induced by the DHA-supplemented diet were observed in the orchidectomized, but not in the healthy group, DHA seems to exert cardioprotective effects in physiopathological situations in which vascular dysfunction exists.

Docosahexaenoic Acid Supplemented Diet Influences the Orchidectomy-Induced Vascular Dysfunction in Rat Mesenteric Arteries

“…The results now presented are in agreement with these previous findings, since TXA 2 , PGI 2 , and PGE 2 are increased from the 6 week post-orchidectomy, as observed in aorta [24] and in mesenteric artery for the case of TXA 2 [32]. However, DHA-supplemented diet decreased prostanoids release near to the control group levels.…”

“…NO release was decreased by castration, as reported earlier in aortas from 6 weeks post-orchidectomized rats [32, 24]. The influence of the DHA-supplemented diet, showed a restoration in NO release levels, closely to the ones from the control group, as previously found in aorta [24].…”

“…Six weeks post-diet all groups increased body weight to a similar extent and blood pressure did not show significant changes. Results already published [24]. …”

“…Although the relationship between decreased levels of sex hormones and increased incidence of cardiovascular disease is established [28, 29], to date there are no studies examining the effect of diet supplemented with DHA when gonadal function is lost. Recently, we have reported positive modifications induced by a DHA-supplemented diet on lipid profile, redox status and vasodilator function of aorta from orchidectomized rats [24]. Taking into account that the mesenteric vascular bed importantly contributes to the control of blood pressure, in the present study we have focused on analyzing the effect of DHA-diet in the vascular function of rat mesenteric artery from orchidectomized rats.…”

“…The mechanisms by which these n-3 PUFAs decrease endothelial dysfunction involve lipid and prostanoid metabolism, leading to secondary favorable effects on blood pressure and thrombosis [23]. Additionally, we have reported the beneficial effect of a DHA-supplemented diet of orchidectomized rats on aorta function [24]. …”