title: Exercise training improves baroreflex sensitivity associated with oxidative stress reduction in ovariectomized rats.
abstract: The protection from coronary events that young women have is sharply reduced at menopause. Oxidative stress and baroreflex sensitivity impairment of the circulation have been demonstrated to increase cardiovascular risk. On the other hand, exercise training has been indicated as a nonpharmacological treatment for many diseases. The aim of the present study was to test the hypothesis that exercise training can improve baroreflex sensitivity associated with reduction in oxidative stress in ovariectomized rats, an experimental model of menopause. Exercise training was performed on a treadmill for 8 weeks. Arterial pressure and baroreflex sensitivity, which were evaluated by tachycardic and bradycardic responses to changes in arterial pressure, were monitored. Oxidative stress was evaluated by chemiluminescence and superoxide dismutase and catalase antioxidant enzyme activities. Exercise training reduced resting mean arterial pressure (112+/-2 vs 122+/-3 mm Hg in the sedentary group) and heart rate (325+/-4 vs 356+/-12 bpm in the sedentary group) and also improved baroreflex sensitivity (tachycardic response, 63% and bradycardic response, 58%). Myocardium (25%) and gastrocnemius muscle (48%) chemiluminescence were reduced, and myocardial superoxide dismutase (44%) and gastrocnemius catalase (97%) activities were enhanced in trained rats in comparison with sedentary rats. Myocardium chemiluminescence was positively correlated with systolic arterial pressure (r=0.6) and inversely correlated with baroreflex sensitivity (tachycardic response, r=-0.8 and bradycardic response, r=-0.7). These results indicate that exercise training in ovariectomized rats improves resting hemodynamic status and reflex control of the circulation, probably associated with oxidative stress reduction, suggesting a homeostatic role for exercise training in reducing cardiovascular risk in postmenopausal women.
authors.affiliation: Heart Institute (InCor), University of Sao Paulo Medical School, Sao Paulo, Brazil.
authors.forename: Maria-Cláudia
authors.initials: MC
authors.lastname: Irigoyen
authors.forename: Janaina
authors.initials: J
authors.lastname: Paulini
authors.forename: Lucinar J F
authors.initials: LJ
authors.lastname: Flores
authors.forename: Karin
authors.initials: K
authors.lastname: Flues
authors.forename: Mariane
authors.initials: M
authors.lastname: Bertagnolli
authors.forename: Edson Dias
authors.initials: ED
authors.lastname: Moreira
authors.forename: Fernanda
authors.initials: F
authors.lastname: Consolim-Colombo
authors.forename: Adriane
authors.initials: A
authors.lastname: Belló-Klein
authors.forename: Kátia
authors.initials: K
authors.lastname: De Angelis
mesh_terms: D000818:Animals; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D002374:Catalase / Q000378:metabolism; D005260:Female; D006321:Heart / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D049449:Luminescence; D008593:Menopause; D023421:Models, Animal; D018482:Muscle, Skeletal / Q000201:enzymology / Q000502:physiology; D009206:Myocardium / Q000201:enzymology; D010052:Ovariectomy; D018384:Oxidative Stress / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D002374:Catalase; D013482:Superoxide Dismutase