Exercise training attenuates cardiovascular adverse remodeling in adult ovariectomized spontaneously hypertensive rats.
OBJECTIVE
To study the combined effects of ovariectomy and regular exercise training on hypertension and on cardiac and aortic remodeling in spontaneously hypertensive rats (SHR).


METHODS
Three-month-old female spontaneously hypertensive rats (SHR) were ovariectomized (ovx) or were left intact (int) and divided in four groups (n = 7): sedentary (sed-ovx), exercise-trained (ex-ovx), sedentary intact (sed-int), and exercise-trained intact (ex-int). The exercise protocol was performed on a motor treadmill for 13 weeks. Blood pressure (BP), left ventricular myocardium and aortic wall were studied by light microscopy and stereology.


RESULTS
Exercise-trained SHR showed a BP reduction of more than 15% compared with the matched sedentary SHR (sed-int: 210 +/- 5 mm Hg, sed-ovx: 225 +/- 4 mm Hg, ex-int: 178 +/- 2 mm Hg, ex-ovx: 180 +/- 3 mm Hg, P < 0.001). Ovariectomy caused adverse cardiac and aortic wall remodeling, including cardiomyocyte hypertrophy, myocardial interstitial reparative fibrosis and vascularization impairment with loss of cardiomyocytes, and aortic tunica media hypertrophy. Exercise training showed beneficial effects, mainly reduced BP, decreased cardiac hypertrophy due to hypertension, and increased myocardial vascularization. Ovariectomy accelerated cardiomyocyte loss in SHR while exercise training offset this process. Exercise training was the main factor influencing the improvement of intramyocardial arteries length density and significantly reduced the aortic wall thickness and increased the density of smooth muscle cell nuclei per tunica media unit area.


CONCLUSIONS
In ovariectomized SHR, exercise training exerts beneficial effects diminishing adverse cardiac and aortic wall remodeling, mainly by reducing interstitial myocardial fibrosis, improving myocardial vascularization, and sustaining the number of cardiomyocytes.
Marques
Claudia M M
CM
Laboratory of Morphometry and Cardiovascular Morphology, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Brazil.
Nascimento
Fernanda A M
FA
Mandarim-de-Lacerda
Carlos A
CA
Aguila
Marcia B
MB
D000818:Animals; D001011:Aorta / Q000473:pathology; D001699:Biometry; D006332:Cardiomegaly / Q000517:prevention & control*; D003331:Coronary Vessels; D005260:Female; D006973:Hypertension / Q000517:prevention & control*; D006984:Hypertrophy; D009206:Myocardium / Q000473:pathology; D010052:Ovariectomy; D010805:Physical Conditioning, Animal; D051381:Rats; D011918:Rats, Inbred SHR; D017540:Tunica Media / Q000473:pathology; D020257:Ventricular Remodeling / Q000502:physiology*