Exercicio fisico e expressão da proteina de estresse HSP72 em musculos de ratos submetidos a diferentes a diferentes tipos de treinamento

AUTOR(ES)
DATA DE PUBLICAÇÃO

1999

RESUMO

Muscle is a tissue with high plasticity, that is, it can change its biochemical and functional characteristics to better cope with different stimulus. Exercise can provide stimulus that induce adaptations in the energy generating, antioxidant defense and myofibrilar systems. But, if the stimulus are toe intense, myofibrils can be submitted to a stressful condition. The generated stress results, on a molecular levei, in a fast production of stress proteins. These proteins have cellular protective functions and appears to be involved in the preparation of cells to survival in the new condition. In the muscle, the stress protein HSP72 is one of the main proteins involved in this mechanism of fast protection against different types of stress (Welch, 1992; Locke et aI., 1994; Hernando e Manso, 1997). The results of the present work indicate that after intense exercise, sedentary rats show an increase of HSP72 levels in the locomotory muscles soleus (oxidative) and semitendinous (glicolytic). Rats submitted to continuous and intermittent training programs of 8 weeks do not show increased HSP72 levels after the same intense exercise, suggesting that the adaptations resulted from the training program increased muscle resistance to exercise stress. When compared to markers of the oxidant and antioxidant systems, the results indicate thatthe higher the HSP72 levels, higher is the activity of citrate synthase (CS) in relation to that of catalase (CA T) and glutathione reductase (GR). It is suggested that HSP72 could represent a secondary defense against protein damage induced by oxidative stress in skeletal muscles. This is supported by the fact that HSP72 has activity of protecting and repaíring proteins, and that the higher the CS activity in relation to CA T and GR a ctivity , higher should be the deleterious effects of the oxidative stress. Moreover, this mechanism appears to function not only in stressful conditions but also constitutively. This work indicate the usefulness of HSP72 as a biomarker of stress conditions in the muscle. In the case of exercise, high HSP72 levels coincide with oxidative stress conditions

ASSUNTO(S)

exercicios fisicos musculos proteinas

ACESSO AO ARTIGO

Documentos Relacionados