RESUMO
We investigated the effects of acute and chronic exercise, prescribed in different intensity zones, but with total load-matched on mitochondrial markers (cytochrome C oxidase subunit IV (COX-IV), mitochondrial transcription factor A (Tfam), and citrate synthase (CS) activity in skeletal muscles, heart, and liver), glycogen stores, aerobic capacity, and anaerobic index in swimming rats. For this, 2 experimental designs were performed (acute and chronic efforts). Load-matched exercises were prescribed below, above, and on the anaerobic threshold (AnT), determined by the lactate minimum test. In chronic programs, 2 training prescription strategies were assessed (monotonous and linear periodized model). Results show changes in glycogen stores but no modification in the COX-IV and Tfam contents after acute exercises. In the chronic protocols, COX-IV and Tfam proteins and CS adaptations were intensity- and tissue-dependent. Monotonous training promoted better adaptations than the periodized model. Training at 80% of the AnT improved both performance variables, emphasizing the anaerobic index, concomitant to CS and COX-IV improvement (soleus muscle). The aerobic capacity and CS activity (gastrocnemius) were increased after 120% AnT training. In conclusion, acute exercise protocol did not promote responses in mitochondrial target proteins. An intensity and tissue dependence were reported in the chronic protocols, highlighting training at 80 and 120% of the AnT. Novelty: Load-matched acute exercise did not enhance COX-IV and Tfam contents in skeletal muscles, heart, and liver. In chronic exercise, COX-IV, Tfam, and CS activity adaptations were intensity- and tissue-dependent. Monotonous training was more efficient than the periodized linear model in adaptations of target proteins and enzymatic activity.
Assuntos
Mitocôndrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Biogênese de Organelas , Condicionamento Físico Animal , Adaptação Fisiológica , Limiar Anaeróbio , Animais , Citrato (si)-Sintase/metabolismo , Proteínas de Ligação a DNA/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Glicogênio/metabolismo , Ácido Láctico/sangue , Masculino , Proteínas Mitocondriais/metabolismo , Ratos , Ratos Wistar , Fatores de Transcrição/metabolismoRESUMO
Several studies have reported that high doses of synthetic anabolic androgenic steroids (AAS) can have serious negative effects on health, including the cardiovascular system. The aim of this study was to evaluate the combined effects of AAS and exercise training on ventricular repolarization and cardiac autonomic modulation in rats. Male Wistar rats were allocated into 4 groups: sedentary rats treated with vehicle, sedentary rats treated with nandrolone decanoate, swimming-trained rats treated with vehicle, and swimming-trained rats treated with nandrolone decanoate. Ventricular repolarization was evaluated by electrocardiographic analysis of QT interval and QT dispersion. Cardiac autonomic modulation was assessed by heart rate variability. Our results show that AAS increased QT interval and QT dispersion in sedentary rats treated with nandrolone decanoate as compared to sedentary rats treated with vehicle, indicating AAS-induced ventricular repolarization abnormalities. When rats treated with nandrolone decanoate were subjected to concomitant exercise training, ventricular repolarization was normalized. On the other hand, AAS-induced reduction in cardiac parasympathetic modulation was not prevented by exercise training. In conclusion, AAS produced cardiac autonomic dysfunction and ventricular repolarization disturbances in rats. Combining an exercise training protocol during the AAS treatment attenuated the ventricular repolarization abnormalities and did not prevent cardiac autonomic dysfunction.
Assuntos
Sistema Nervoso Autônomo/efeitos dos fármacos , Sistema Nervoso Autônomo/fisiologia , Ventrículos do Coração/efeitos dos fármacos , Coração/inervação , Condicionamento Físico Animal , Congêneres da Testosterona/farmacologia , Tecido Adiposo/citologia , Tecido Adiposo/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Peso Corporal/fisiologia , Relação Dose-Resposta a Droga , Eletrocardiografia/efeitos dos fármacos , Coração/efeitos dos fármacos , Coração/fisiologia , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Masculino , Tamanho do Órgão/efeitos dos fármacos , Tamanho do Órgão/fisiologia , Ratos , Ratos Wistar , Função Ventricular/efeitos dos fármacosRESUMO
We assessed cardiac function (echocardiographic) and glucose transporter 4 (GLUT4) expression (Western blot) in response to 10 weeks of aerobic training (treadmill) prior to acute myocardial infarction (AMI) by ligation of the left coronary artery in spontaneously hypertensive rats. Animals were allocated to sedentary+sham, sedentary+AMI, training+sham, and training+AMI. Aerobic training prior to AMI partially preserves heart function. AMI and/or aerobic training increased GLUT4 expression. However, those animals trained prior to AMI showed a greater increase in GLUT4 in cardiomyocytes.
Assuntos
Transportador de Glucose Tipo 4/genética , Infarto do Miocárdio/genética , Miocárdio/metabolismo , Condicionamento Físico Animal , Doença Aguda , Animais , Glicemia/metabolismo , Ecocardiografia , Feminino , Transportador de Glucose Tipo 4/sangue , Masculino , Miócitos Cardíacos/metabolismo , Ratos , Ratos Endogâmicos SHRRESUMO
The effects of exercise training (ExT) on the pressor response elicited by potassium cyanide (KCN) in the rat model of ischemia-induced heart failure (HF) are unknown. We evaluated the effects of ExT on chemoreflex sensitivity and its interaction with baroreflex in rats with HF. Wistar rats were divided into four groups: trained HF (Tr-HF), sedentary HF (Sed-HF), trained sham (Tr-Sham), and sedentary sham (Sed-Sham). Trained animals underwent to a treadmill running protocol for 8 weeks (60 m/day, 5 days/week, 16 m/min). After ExT, arterial pressure (AP), baroreflex sensitivity (BRS), peripheral chemoreflex (KCN: 100 µg/kg body mass), and cardiac function were evaluated. The results demonstrate that ExT induces an improvement in BRS and attenuates the pressor response to KCN relative to the Sed-HF group (P < 0.05). The improvement in BRS was associated with a reduction in the pressor response following ExT in HF rats (P < 0.05). Moreover, ExT induced a reduction in left ventricular end-diastolic pressure and pulmonary congestion compared with the Sed-HF group (P < 0.05). The pressor response to KCN in the hypotensive state is decreased in sedentary HF rats. These results suggest that ExT improves cardiac function and BRS and attenuates the pressor response evoked by KCN in HF rats.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Terapia por Exercício , Insuficiência Cardíaca/fisiopatologia , Insuficiência Cardíaca/terapia , Cianeto de Potássio/farmacologia , Animais , Barorreflexo/fisiologia , Pressão Sanguínea/fisiologia , Hiperemia/fisiopatologia , Hiperemia/terapia , Hipotensão/induzido quimicamente , Hipotensão/fisiopatologia , Fígado/irrigação sanguínea , Pulmão/irrigação sanguínea , Masculino , Nitroprussiato/farmacologia , Ratos , Disfunção Ventricular Esquerda/terapiaRESUMO
The current cages commonly used in animal experiments can prevent rats from engaging in most forms of natural locomotion behaviors. These animals tend to exhibit sedentary habits. Here, we show that a combination of wide housing space and training exercise helps to reduce white adipose mass and to increase brown adipose mass. Thus, this combination is a useful strategy for truly enhancing the physical fitness of captive rats commonly used in exercise-related interventional studies and to maximize their welfare.