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. 2015 Apr 29;10(4):e0125388.
doi: 10.1371/journal.pone.0125388. eCollection 2015.

Aerobic Exercise Training Prevents the Onset of Endothelial Dysfunction via Increased Nitric Oxide Bioavailability and Reduced Reactive Oxygen Species in an Experimental Model of Menopause

Viviane A V N Braga  1 , Gisele K Couto  2 , Mariana C Lazzarin  1 , Luciana V Rossoni  2 , Alessandra Medeiros  1
Affiliations

Aerobic Exercise Training Prevents the Onset of Endothelial Dysfunction via Increased Nitric Oxide Bioavailability and Reduced Reactive Oxygen Species in an Experimental Model of Menopause

Viviane A V N Braga et al. PLoS One. .

Abstract

Objective: Previous studies have shown that estrogen deficiency, arising in postmenopause, promotes endothelial dysfunction. This study evaluated the effects of aerobic exercise training on endothelial dependent vasodilation of aorta in ovariectomized rats, specifically investigating the role of nitric oxide (NO) and reactive oxygen species (ROS).

Methods: Female Wistar rats ovariectomized (OVX - n=20) or with intact ovary (SHAM - n=20) remained sedentary (OVX and SHAM) or performed aerobic exercise training on a treadmill 5 times a week for a period of 8 weeks (OVX-TRA and SHAM-TRA). In the thoracic aorta the endothelium-dependent and -independent vasodilation was assessed by acetylcholine (ACh) and sodium nitroprusside (SNP), respectively. Certain aortic rings were incubated with L-NAME to assess the NO modulation on the ACh-induced vasodilation. The fluorescence to dihydroethidium in aortic slices and plasma nitrite/nitrate concentrations were measured to evaluate ROS and NO bioavailability, respectively.

Results: ACh-induced vasodilation was reduced in OVX rats as compared SHAM (Rmax: SHAM: 86±3.3 vs. OVX: 57±3.0%, p<0.01). Training prevented this response in OVX-TRA (Rmax: OVX-TRA: 88±2.0%, p<0.01), while did not change it in SHAM-TRA (Rmax: SHAM-TRA: 80±2.2%, p<0.01). The L-NAME incubation abolished the differences in ACh-induced relaxation among groups. SNP-induced vasodilation was not different among groups. OVX reduced nitrite/nitrate plasma concentrations and increased ROS in aortic slices, training as effective to restore these parameters to the SHAM levels.

Conclusions: Exercise training, even in estrogen deficiency conditions, is able to improve endothelial dependent vasodilation in rat aorta via enhanced NO bioavailability and reduced ROS levels.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Concentration—response curve to acetylcholine (A) and sodium nitroprusside (B) in aortic rings from SHAM, SHAM-TRA, OVX and OVX-TRA.
The numbers shown in the legend represent the number of animals analyzed in each group. Results are expressed as means±SEM. Two-way ANOVA: *p<0.01 in comparison to SHAM, # p<0.01 in comparison to OVX.
Fig 2
Fig 2. Effect of L-NAME (100 μM) on the concentration—response curve of ACh in aortic rings from SHAM vs SHAM-TRA (A) and OVX vs OVX-TRA (B).
The numbers shown in the graphs represent the number of animals analyzed in each group. Results are expressed as means±SEM. Two-way ANOVA: & p<0.01 in comparison to control; *p<0.01 in comparison to SHAM, # p<0.01 in comparison to OVX.
Fig 3
Fig 3. Nitrite/nitrate plasma levels from SHAM, SHAM-TRA, OVX and OVX-TRA rats.
Results are expressed as means±SEM. The numbers shown in bars represent the number of animals analyzed in each group. Two-way ANOVA: *p<0.01 in comparison to SHAM, # p<0.01 in comparison to OVX.
Fig 4
Fig 4. Representative images of aortic slices from SHAM, SHAM-TRA, OVX and OVX-TRA rats, in the absence (upper panel) and presence (lower panel) of the superoxide dismutase mimetic, MnTMPyP (A). Quantification of fluorescence intensity emitted by DHE oxidation in aortic slices in the absence and presence of the MnTMPyP as an indicative of reactive oxygen species in SHAM, SHAM-TRA, OVX and OVX-TRA rats (B).
The numbers shown in bars represent the number of animals analyzed in each group. Results are expressed as means±SEM. Two-way ANOVA: *p<0.01 in comparison to SHAM, # p<0.01 in comparison to OVX.
See this image and copyright information in PMC

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