ABSTRACT
Purpose@#The effects of aerobic exercise training on soleus muscle morphology, mitochondria-mediated apoptotic signaling, and atrophy/hypertrophy signaling in ovariectomized rat skeletal muscle were investigated. @*Methods@#Female Sprague-Dawley rats were divided into control (CON), ovariectomy (OVX), and ovariectomy plus exercise (OVX+EX) groups. After ovarian excision, exercise training was performed using a rat treadmill at 20 m/min, 50 min/day, 5 days/week for 12 weeks. Protein levels of mitochondria-mediated apoptotic signaling and atrophy/hypertrophy signaling in the skeletal muscle (soleus) were examined through western immunoblot analysis. @*Results@#The number of myocytes and myocyte cross-sectional area (CSA) were increased and the extramyocyte space was decreased in the OVX group compared to those in the CON group. However, aerobic exercise training significantly increased myocyte CSA and decreased extramyocyte space in the OVX+EX group compared to those in the OVX group. The protein levels of proapoptotic signaling and muscle atrophy signaling were significantly increased, whereas the protein levels of muscle hypertrophy signaling were significantly decreased in the OVX group compared to that in the CON group. Aerobic exercise training significantly decreased the protein levels of proapoptotic signaling and increased the protein level of antiapoptotic protein in the OVX+EX group compared to that in the OVX group. Aerobic exercise training significantly increased the protein levels of hypertrophy signaling and decreased protein levels of atrophy signaling in the OVX+EX group compared to those in the OVX group. @*Conclusions@#Treadmill exercise improved estrogen deficiency-induced impairment in skeletal muscle remodeling, mitochondria-mediated apoptotic signaling, and atrophy/hypertrophy signaling in skeletal muscle.
ABSTRACT
The prevalence of non-alcoholic fatty liver disease (NAFLD) is steadily increasing in conjunction with increases in obesity, type 2 diabetes, and physical inactivity. NAFLD encompasses a spectrum of conditions associated with lipid deposition in hepatocytes, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH) and to advanced fibrosis and cirrhosis. A large proportion of patients with NAFLD have co-existing metabolic syndrome, which is also a major risk factor of cardiovascular disease. There is an urgency to recognize that NAFLD poses an additional risk for cardiovascular disease and should involve early aggressive risk factor modification. A lifestyle modification of diet and physical activity targeting substantial weight loss is considered as the first-line defense system against NAFLD. In this review, the roles of physical activity are discussed as an effective and safe means to combat NAFLD and its metabolic complications.