Resistance training and caloric restriction prevent systolic blood pressure rise by improving the nitric oxide effect on smooth muscle and morphological changes in the aorta of ovariectomized rats

Figures

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  Fig 1. Scheme of the experimental period. OVX = Ovariectomy procedures; SBP = Systolic blood pressure measurements; P0 = 24 h before OVX; P1 = 10 days after OVX and 24 h before RT and CR starting protocols; P2 = seventh week after RT and CR protocol starting and P3 = 24 h before euthanasia.

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  Fig 2. Effects of ovariectomy (OVX), resistance training (RT), caloric restriction (CR) and their association (RT+CR) in aortic rings on endothelium-dependent relaxation induced by acetylcholine (ACh) and endothelium-independent relaxation induced by sodium nitroprusside (SNP). (A) Concentration response curve to ACh; (B) Concentration response curve to SNP; (C) The potency (pD2) relaxant effect by ACh and D) The potency (pD2) relaxant effect by SNP. Superscript letters represent significant difference between groups by a one-way ANOVA with post hoc Tukey test (p<0.05), a ≠ b, b ≠ c, c ≠ d.

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  Fig 3. Effects of ovariectomy (OVX), resistance training (RT), caloric restriction (CR) and their association (RT+CR) on pro, intermediate and active matrix metalloproteinase 2 (MMP-2). (A) Representative image of MMP-2 activity by zymography; (B) Pro MMP-2; (C) Values of Intermediate MMP-2; (D) Active MMP-2. Letters superscript represent significant difference between groups by a one-way ANOVA with post hoc Tukey test (p<0.05), a ≠ b, b ≠ c, c ≠ d.

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  Fig 4. Ovariectomy (OVX), resistance training (RT), caloric restriction (CR) and their association (RT+CR) on structural modifications induced in the thoracic aorta. (A) Representative photomicrography of thoracic aorta of Holtzman rats stained by hematoxylin and eosin (H&E); (B) Values of lumen area (mm2); (C) MT, Media thickness (mm); (D) CSA (mm2) (Cross-sectional area); and (E) Values of media-to-lumen ratio (M/L), in percentage (%). Superscript letters represent significant difference (p<0.05) between groups by a one-way ANOVA with post hoc Tukey test (all groups), a ≠ b, b ≠ c, c ≠ d.

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  Fig 5. Effects of ovariectomy (OVX), resistance training (RT), caloric restriction (CR) and their association (RT+CR) on percentage of collagen content I and III in the aortic wall, stained with Picrosirius Red. Superscript letters represent significant difference between groups by a one-way ANOVA with post hoc Tukey test (p<0.05), a ≠ b, b ≠ c, c ≠ d.

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  Fig 6. Effects of ovariectomy (OVX), resistance training (RT), caloric restriction (CR) and their association (RT+CR) on (A) Histological change in aortic wall structure in categories: Category 1 (Red)- Well-defined endothelial cells, smooth muscle cell without visible changes, linear and parallel elastic fibers, interspersed with smooth muscle cells; Category 2 (Green)- Less endothelial cells, fewer smooth muscle cells, elastic fibers slightly undulated with minimal space and fewer smooth muscle cells between them; Category 3 (Blue)- Few endothelial cells, misshapen structures, altered, wrinkled, thick elastic fibers with minimal space and less smooth muscle between them. The values are presented as percentages (%) with no statistical tests performed. Colors arrows indicate: black- endothelial cells; yellow- smooth muscle cells; and white- elastic fibers; (B) Histological Changes in Aortic Wall (%), and (C) Number of elastic fibers, shown as units, stained with Trichrome-Masson. Letters superscript represent significant difference between groups by a one-way ANOVA with post hoc Tukey test (p<0.05), a ≠ b, b ≠ c, c ≠ d.

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  Fig 7. Effect of ovariectomy (OVX), resistance training (RT), caloric restriction (CR) and their association (RT+CR) in (A) Evolution of systolic blood pressure (SBP) (mmHg). P0- 24 h before OVX; P1- ten days after OVX and twenty-four hours before starting RT and CR protocols; P2- seven weeks after starting RT and CR protocol; P3- 24 h before euthanasia; and (B) Heart rate in beats per minute (BPM) in initial and final experimental period. Superscript letters represent significant differences between groups by a one-way ANOVA with post hoc Tukey test (p<0.05), a ≠ b, b ≠ c, c ≠ d.