Este estudo investigou os efeitos do treinamento em corrida de baixa intensidade (TCBI) sobre propriedades estruturais e mecânicas da epífise proximal do fêmur de ratas osteopênicas. Ratas Wistar [idade = 20 semanas; massa corporal = 271,42 ± 17,6 g] foram submetidas à ovariectomia (OVX) ou laparotomia (SHAM) e alocadas em quatro grupos: corrida OVX (CO, n = 12), controle OVX (CONO, n = 12), corrida SHAM (CS, n = 12) e controle SHAM (CONS, n = 12). Quinze dias pós-cirurgia, os grupos CO e CS foram submetidos ao TCBI em esteira (16 m/min, 60 min/dia, cinco dias/semana) por 10 semanas. O TCBI não alterou os efeitos deletérios da osteopenia induzida por ovariectomia sobre a densidade mineral do fêmur, a quantidade de osso trabecular no trocanter e colo do fêmur, a tenacidade e a força máxima de fratura do colo do fêmur de ratas.

This study investigated the effects of low-intensity running training (LIRT) on the structural and mechanical properties of the proximal femoral epiphysis in osteopenic female rats. Female Wistar rats [age = 20 weeks, body mass = 271.42 ± 17.6 g] were subjected to ovariectomy (OVX) or laparotomy (SHAM) and divided into four groups: running OVX (RO, n = 12), control OVX (CO, n = 12), running SHAM (RS, n = 12) and control SHAM (CS, n = 12). Two weeks after surgery RO and RS groups were submitted to a progressive LITR on a treadmill (60 min / day, 5 days / week) for 10 weeks. The LIRT did not alter the deleterious effects induced by ovariectomy on the femoral bone mineral density, the quantity of trabecular bone in the femoral great trocanter and neck, and femoral neck tenacity and resistance to fracture in female rats.

Este estudio investigó los efectos del entrenamiento en carera de baja intensidad (ECBI) en las propiedades estructurales y mecánicas de la epífisis proximal femoral de ratas osteopénicas. Ratas Wistar con edad de 20 semanas (peso corporal: 271.42 ± 17,6 g) fueran sometidas a ooforectomía (OVX) o laparotomía (SHAM) y asignados en cuatro grupos: carera OVX (CO, n = 12), control OVX (CONO, n = 12), carera SHAM (CS, n = 12) y control SHAM (CONS, n = 12). Quince días después de la cirugía los grupos CO y CS fueran sometidos al ECBI (16 m/ min; 60 min/día, 5 dias/semana) durante 10 semanas. El ECBI no cambió los efectos deletéreos de la osteopenia inducida por ooforectomía sobre la densidad mineral del fémur, la cantidad de hueso trabecular en el trocánter y cuello del fémur, la tenacidad y la resistencia ósea a la fractura del cuello del fémur de ratas.

OBJECTIVES: The present study was performed to investigate 1) whether aerobic exercise training prior to myocardial infarction would prevent cardiac dysfunction and structural deterioration and 2) whether the potential cardiac benefits of aerobic exercise training would be associated with preserved morphological and contractile properties of cardiomyocytes in post-infarct remodeled myocardium. METHODS: Male Wistar rats underwent an aerobic exercise training protocol for eight weeks. The rats were then assigned to sham surgery (SHAM), sedentary lifestyle and myocardial infarction or exercise training and myocardial infarction groups and were evaluated 15 days after the surgery. Left ventricular tissue was analyzed histologically, and the contractile function of isolated myocytes was measured. Student's t-test was used to analyze infarct size and ventricular wall thickness, and the other parameters were analyzed by the Kruskal-Wallis test followed by Dunn's test or a one-way analysis of variance followed by Tukey's test (p<0.05). RESULTS: Myocardial infarctions in exercise-trained animals resulted in a smaller myocardial infarction extension, a thicker infarcted wall and less collagen accumulation as compared to myocardial infarctions in sedentary animals. Myocardial infarction-induced left ventricular dilation and cardiac dysfunction, as evaluated by +dP/dt and -dP/dt, were both prevented by previous aerobic exercise training. Moreover, aerobic exercise training preserved cardiac myocyte shortening, improved the maximum shortening and relengthening velocities in infarcted hearts and enhanced responsiveness to calcium. CONCLUSION: Previous aerobic exercise training attenuated the cardiac dysfunction and structural deterioration promoted by myocardial infarction, and such benefits were associated with preserved cardiomyocyte morphological and contractile properties.