Effect of eccentric training on mitochondrial function and oxidative stress in the skeletal muscle of rats

Abstract

The objective of the present study was to investigate the effects of eccentric training on the activity of mitochondrial respiratory chain enzymes, oxidative stress, muscle damage, and inflammation of skeletal muscle. Eighteen male mice (CF1) weighing 30-35 g were randomly divided into 3 groups (N = 6): untrained, trained eccentric running (16°; TER), and trained running (0°) (TR), and were submitted to an 8-week training program. TER increased muscle oxidative capacity (succinate dehydrogenase and complexes I and II) in a manner similar to TR, and TER did not decrease oxidative damage (xylenol and creatine phosphate) but increased antioxidant enzyme activity (superoxide dismutase and catalase) similar to TR. Muscle damage (creatine kinase) and inflammation (myeloperoxidase) were not reduced by TER. In conclusion, we suggest that TER improves mitochondrial function but does not reduce oxidative stress, muscle damage, or inflammation induced by eccentric contractions.

Role of hydrogen sulfide in skeletal muscle biology and metabolism

“…Moreover, eccentric exercise causes ROS accumulation [35] leading to mild muscle damage. Given that H 2 S can act as a ROS scavenger [36] and/or mild mitochondrial uncoupler, it is of interest to know whether chronic low doses of H 2 S exposure might prolong longevity and enhance benefits of exercise by limiting ROS-induced cellular damage to macro molecules.…”

Mitochondrial dysfunction and autophagy responses to skeletal muscle stress

“…Mitochondria are appreciated as contributing to the regenerative potential, plasticity, and overall quality of skeletal muscle, and, therefore, investigating the muscle fiber-mitochondrial relationship may produce important targets for rehabilitation and disease prevention. However, there appear to be inconsistencies in the literature regarding what types of muscle stressors elicit mitochondrial dysfunction (20, 30, 31, 33), as well as the extent to which autophagy is necessary for the timely repair of mitochondrial dysfunction after muscle stress (6). Herein, we relied upon oxygen consumption as the marker of mitochondrial function, enzyme activities of succinate dehydrogenase and citrate synthase as markers of mitochondrial content, and a muscle-specific Ulk1 knockout mouse to test the necessity of autophagy for the recovery of mitochondrial function and content.…”

“…Less severe muscle stressors, like eccentric contraction-induced injuries, mainly disrupt excitation-contraction coupling and result in an initial 40%-60% decline in muscle contractility (38). There have been conflicting reports of mitochondrial oxygen consumption rates after downhill treadmill running, a mild and indirect form of eccentric contraction-induced injury in mice with some reporting no changes in mitochondrial respiration and others reporting transient changes immediately and up to 48 hours after the injury (24, 30, 31, 33). Additionally, this injury model is reported to elicit oxidative damage in the form of a greater presence of protein carbonyls and oxidized lipids that could implicate mitochondrial dysfunction (26, 33).…”

Efeito da suplementação de creatina, associada ou não ao treinamento de força, sobre a peroxidação lipídica em mulheres idosas

“…S et al 33 suplementaram ratos com creatina por duas semanas e submeteram os animais a uma sessão de exercício em esteira declinada até a exaustão. Os autores também não observaram diferenças na produção de superóxido, nos níveis de espécies reativas ao ácido tiobarbitúrico (TBARS), e na atividade das enzimas superóxido dismutase, catalase e glutationa peroxidase no músculo quadríceps dos animais suplementados com creatina quando comparados aos animais suplementados com solução salina, indicando que a ingestão de creatina não modula o estresse oxidativo após um exercício de ação excêntrica 19 . Estudos em humanos também corroboram os presentes achados.…”

“…Amostra e desenho experimental morfofuncionais e biomoleculares no organismo, podendo atenuar ou até mesmo reverter diferentes quadros patológicos [16][17][18] . Dentre essas adaptações, ressalta-se uma diminuição da produção de EROs e/ou um aumento da defesa antioxidante total [19][20][21][22][23][24] . Interessantemente, o treinamento de força parece ocasionar adaptações antioxidantes similares ao treinamento físico aeróbio 25 .…”