Oxidative stress in immobilization and remobilization: Studies of its characteristics and the application of purified Chinese medicine extract, verbascoside

Immobilization of the limb, as a means of treating musculoskeletal injuries, is commonly performed in clinical practice. Oxidative stress, often identified in immobilized muscle, has been proposed to be one of the factors to muscle damage during immobilization and remobilization. There are a number of key questions that will need to be addressed: (a) When oxidative stress occurs, how long will it last during immobilization and remobilization; (b) Dose oxidative stress manifest at a local immobilized tissue level or is there a systemic response; (c) Can verbascoside, a purified Chinese medicine with known antioxidant function, moderate the oxidative stress resulted from immobilization and remobilization. The objectives of this Ph.D study are: (1) To characterize the status of oxidative stress both in blood and skeletal muscles during immobilization and remobilization; (2) To investigate the changes in membrane fluidity of erythrocyte and muscle mitochondria as the consequence of oxidative damage; (3) To evaluate the effects of verbasocide on oxidative stress and oxidative damage during immobilization and remobilization.; The results indicated that there was a significantly increase in oxidative stress in plasma and a decrease in erythrocyte membrane fluidity during immobilization and remobilization. The changes of lipid peroxidation, glutathione levels in plasma and erythrocyte membrane fluidity during immobilization showed close negative association. Oxidative stress level peaked on day 7 of immobilization and erythrocyte membrane fluidity decreased to the lowest level at the same time point. During remobilization, plasma oxidative stress level re-peaked on day 2. The data from muscle samples showed that single limb immobilization increased oxidative stress in muscles both from immobilized and contralateral limbs; remobilization on day 7 magnified this change. The change in mitochondria membrane fluidity corresponded with that of oxidative stress. SOL (red) muscle showed greater atrophy induced by immobilization. Verbascoside was shown to significantly reduce oxidative stress level induced by immobilization and remobilization and attenuate the decrease of membrane fluidity. While the treatment with verbascoside did not have any influence on oxidative stress in both muscle and blood in rabbit under normal conditions. (Abstract shortened by UMI.)...