Effect of 5-day vitamin E supplementation on muscle injury after downhill running in rats

Abstract

Antioxidant supplementation has been suggested to prevent exercise-induced muscle injury, but the findings are inconsistent. The objective of this study was to investigate the potential protective role of vitamin E treatment against eccentric exercise-induced muscle injury by examining morphological and functional alterations in rat soleus muscle after downhill running as well as muscle injury markers in the blood. Sixty adult male Wistar rats were randomly assigned to vitamin E-treated or placebo-treated groups studied at rest, immediately post-exercise or 48 h post-exercise (n = 10 per group). Vitamin E was administered by daily intraperitoneal injections of 100 mg/kg body mass of DL: -α-tocopheryl acetate for five consecutive days prior to exercise, resulting in the doubling of its plasma concentration. Downhill running resulted in significant (P < 0.05) changes in all injury markers for the placebo-treated rats at 0 and 48 h post-exercise. However, significantly smaller soleus muscle single-twitch tension (P (t)) and unfused (40 Hz) tetanic force, and greater plasma creatine kinase (CK) and lactate dehydrogenase (LD) activities compared with the control were found only immediately post-exercise for the vitamin E-treated rats (P < 0.05). Maximal tetanic force (P (o)) did not decline significantly compared to sedentary controls at neither time points measured. The vitamin E-treated rats had significantly (P < 0.05) higher soleus muscle P (t) immediately post-exercise than the placebo-treated rats as well as lower plasma CK and LD activity 48 h post-exercise. However, there was no difference in P (o) decline between groups at either time points measured. Vitamin E-treated rats had less pronounced morphological alterations in muscle in the immediate and 48-h post-exercise period. In conclusion, the effect of short-term vitamin E supplementation against eccentric exercise-induced muscle injury did not appear to be physiologically significant, because vitamin E failed to prevent the decline in the functional measure of P (o) compared to the placebo conditions.

Redox biology of exercise: an integrative and comparative consideration of some overlooked issues

“…Despite the progress of analytic techniques and the refinement of study designs, striking disagreement exists among studies regarding the influence of antioxidant supplementation on physical performance and redox homeostasis. Indeed, several studies have indicated that antioxidant supplementation induces a positive effect (Jakeman and Maxwell, 1993;Shafat et al, 2004), a negative effect (Gomez-Cabrera et al, 2008;Ristow et al, 2009) or no effect (Yfanti et al, 2010;Kyparos et al, 2011;Theodorou et al, 2011) on muscle performance. Likewise, several studies have reported that antioxidant supplementation attenuates oxidative stress (Close et al, 2006;Kinnunen et al, 2009), others have reported that it induces a pro-oxidant effect (McAnulty et al, 2005;Versari et al, 2006) and others have reported that it does not affect redox homeostasis (Rytter et al, 2010;Theodorou et al, 2011).…”

Low-Frequency Fatigue as an Indicator of Eccentric Exercise-Induced Muscle Injury: The Role of Vitamin E

“…The relatively little data available from human [27–31] and animal [32–34] studies have failed to show consistently any protective effect of vitamin E on muscle force deficit caused by eccentric contraction-biased exercise. Only in the study of Shafat et al [35], in which though a combination of vitamins E and C was administered, attenuation of the force decline following eccentric exercise in the supplemented group was reported.…”

“…Indeed, it has been recently demonstrated in vitamin-E-supplemented rats that, even though maximal isometric tetanic force ( P o ) was not clearly spared following eccentric contraction-biased exercise, single twitch force ( P t ), which reflects Ca 2+ kinetics in the muscle [36], declined significantly less compared to the placebo conditions [32]. Based on this evidence, we hypothesized that any potential effect of vitamin E treatment to attenuate muscle injury-induced force decline could be better tested by utilizing a low-frequency stimulation protocol.…”

“…To accomplish this objective, vitamin E, a nutritional compound know to have some prophylactic effects on injury-induced force deficit [32, 35], was employed. Vitamin-E-treated or placebo-treated rats ran downhill on a treadmill and studied at rest, immediately postexercise or 48 h postexercise.…”

The Effect of Caffeine Supplementation on Exercise Performance Evaluated by a Novel Animal Model

“…For rodents, this is a potent stressor 10,11 . Other types of models force the animals to run in treadmills [12][13][14] , using electric shocks 15,16 or brushes 17 to motivate them. An extensive literature search did not find experiments utilizing grouped animals and adding their combined activity to assess exercise performance or propensity that could be used to compare in animals, point by point, the seven conclusions derived by the International Society of Sports Nutrition from humans 18 .…”