Moderate regular exercise is thought to be good for health, to help to retard aging and reduce incidence of age-related diseases in aged animals and elderly people. Mechanisms of these beneficial influences are not fully understood. We have investigated effects of regular exercise on oxidative modifications of proteins and DNA, and proteasome activities that can degrade oxidatively modified proteins as well as oxidative status and NF-kB in aging rat tissues.
Young (4 week-old) and middle-aged (14 month-old) rats were subjected to swimming exercise of 5 days a week for 60 to 90 min per day. Nine weeks of the regular exercise resulted in a significant decrease in the protein carbonyls in the brain with concomitant promotion of cognitive functions as revealed by passive and active avoidance tests. The proteasome activity in the brain, cardiac and skeletal muscles was found to be upregulated by the regimen. In other experiment, 8 weeks of regular treadmill running in aged (28 months old) rats resulted in attenuation of age-related increase in 8-hydroxy-2'-deoxyguanosine content in the DNA of gastrocnemius muscle although the effect was not evident in middle-aged (18 month-old) animals. The formation of reactive oxygen species (ROS) in the liver increased with age and the exercise training decreased the rate of ROS formation in the two age groups. The reduced glutathione level was higher and the oxidized glutathione was significantly lower in exercised groups compared with the sedentary controls. Age-associated increase in NF-kB activity detected by electrophoretic gel shift assay was attenuated by the exercise. The content of p50 and p65 subunits of NF-kB increased with age and decreased by the training.
Thus, regular exercise is suggested to be able to induce adaptive molecular response even at old ages that may reduce age-related increase in inflammatory and other detrimental consequences caused by oxidative stress.