Effects of Vitamin E Intake and Voluntary Wheel Running on Whole-Body and Skeletal Muscle Metabolism in...

Background/Objectives: Ovariectomized rodents experience metabolic dysfunction in whole-body and skeletal muscle. A disrupted balance between oxidative stress and antioxidants might exacerbate metabolic dysfunction in ovariectomized rodents. Dietary antioxidants, such as vitamin E intake, before or during exercise would be beneficial by mitigating the exercise-induced increase in oxidative stress in ovariectomized rodents. The purpose of the current study was to investigate the potential effect of vitamin E intake combined with voluntary exercise on whole-body and skeletal muscle metabolism in ovariectomized mice. Methods: This study used C57BL/6J wild-type female mice (n = 40, 8 weeks old), which were randomly assigned into sham (SHM), ovariectomy (OVX), ovariectomy with exercise (OVXVE), ovariectomy with vitamin E (OVXV), ovariectomy with exercise and vitamin E (OVXVE) groups. Body composition, resting metabolic rate, glucose tolerance, skeletal muscle mitochondrial function, and protein contents were assessed using dual-energy x-ray absorptiometry, indirect calorimetry, glucose tolerance test, O₂K OROBOROS, and Western blot, respectively. Results: The combined treatment of vitamin E and voluntary wheel running did not show a beneficial effect on whole-body metabolism such as fat mass, energy expenditure, and glucose tolerance. However, independent of exercise intervention, vitamin E intake enhanced mitochondrial function, Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC1-a), and adenosine monophosphate-activated protein kinase (AMPK) levels and also reduced oxidative stress in the skeletal muscles of ovariectomized mice. Specifically, in the soleus muscle, vitamin E intake enhanced mitochondrial function and PGC1-a content (p < 0.05). In the gastrocnemius muscle, vitamin E intake enhanced PGC1-a and AMPK levels and reduced a marker of oxidative stress (p < 0.05). Conclusions: Vitamin E, as a potent antioxidant, may play a crucial role in maintaining skeletal muscle health in ovariectomized mice. More studies are necessary to investigate whether this finding is applicable to women.