Normal adaptations to exercise despite protection against oxidative stress

Abstract

It has been reported that supplementation with the antioxidant vitamins C and E prevents the adaptive increases in mitochondrial biogenesis and GLUT4 expression induced by endurance exercise. We reevaluated the effects of these antioxidants on the adaptive responses of rat skeletal muscle to swimming in a short-term study consisting of 9 days of vitamins C and E with exercise during the last 3 days and a longer-term study consisting of 8 wk of antioxidant vitamins with exercise during the last 3 wk. The rats in the antioxidant groups were given 750 mg·kg body wt Ϫ1 ·day Ϫ1 vitamin C and 150 mg·kg body wt Ϫ1 ·day Ϫ1 vitamin E. In rats euthanized immediately after exercise, plasma TBARs were elevated in the control rats but not in the antioxidant-supplemented rats, providing evidence for an antioxidant effect. In rats euthanized 18 h after exercise there were large increases in insulin responsiveness of glucose transport in epitrochlearis muscles mediated by an approximately twofold increase in GLUT4 expression in both the short-and long-term treatment groups. The protein levels of a number of mitochondrial marker enzymes were also increased about twofold. Superoxide dismutases (SOD) 1 and 2 were increased about twofold in triceps muscle after 3 days of exercise, but only SOD2 was increased after 3 wk of exercise. There were no differences in the magnitudes of any of these adaptive responses between the control and antioxidant groups. These results show that very large doses of antioxidant vitamins do not prevent the exercise-induced adaptive responses of muscle mitochondria, GLUT4, and insulin action to exercise and have no effect on the level of these proteins in sedentary rats. ascorbic acid; ␣-tocopherol; peroxisome proliferator-activated receptor-␥ coactivator-1␣; mitochondria; superoxide dismutase TWO ARTICLES HAVE BEEN PUBLISHED RECENTLY reporting that taking the vitamin ascorbic acid (vitamin C) or the combination of ascorbic acid and ␣-tocopherol (vitamin E) prevents the adaptive responses of skeletal muscle to endurance exercise. In the first study, Gomez-Cabrera et al. (6) reported that men taking 1.0 g/day ascorbic acid (vitamin C) had a markedly reduced increase in maximal oxygen uptake (V O 2 max ) in response to 8 wk of endurance training. They also reported that giving rats ascorbic acid prevented adaptive increases in enzyme levels in skeletal muscle and severely reduced the increase in endurance induced by a treadmill-running program. In the other study, Ristow et al. (23) evaluated the effects of taking ascorbic acid and ␣-tocopheral on adaptive responses to a 4-wk-long exercise program, the major component of which was circuit training. The study involved two groups of men, one trained and the other untrained, at the start of the study.Ristow et al. (23) interpreted their findings as evidence that antioxidant vitamins prevent exercise training-induced increases in insulin sensitivity and in skeletal muscle peroxisome proliferator-activated receptor-␥ (PPAR␥) coactivator-1␣ PGC-1␣, PPAR␥, and s...

Targeting of mitochondrial reactive oxygen species production does not avert lipid-induced insulin resistance in muscle tissue from mice

“…Interestingly, these two markers were normalised to LF levels upon ROS sequestering. This finding is in line with other reports showing that antioxidant supplementation suppresses exercise-induced mitochondrial biogenesis [43,44], suggesting a potential role of ROS in mitochondrial biogenesis, although not all studies support this conclusion [45].…”

PGC-1α Mediated Muscle Aerobic Adaptations to Exercise, Heat and Cold Exposure

“…In contrast to the above findings, antioxidant supplementation in rodents has shown to have no effect on the expression of mitochondrial transcription factors (NRF1, NRF2 and Tfam) respiratory chain complexes (I-V), PGC-1α or upstream signalling activity (p38 MAPK and AMPK) following acute and chronic endurance exercise (Higashida et al, 2011;. Likewise, research within humans has shown that Vitamin C and E supplementation during a 12-week intense endurance training program had no influence on improvements in VO2max, power output at VO2max and power output at lactate threshold (Yfanti et al, 2010).…”

Ascorbic Acid and Performance: A Review

“…Higashida et al studied the combined effect of vitamin C (750 mg / kg body weight / day) and vitamin E (150 mg kg body weight / day) supplemented on the adaptive responses training-induced muscle mitochondria and sensitivity to insulin in rats. Based on the results of this study, supplementation of vitamin C and E does not have an inhibitory effect or a promoter effect on the adaptive responses related to mitochondria and glucose metabolism in skeletal muscle to chronic exercise [23].…”