THE EFFECTS OF EXERCISE ON OXIDATION OF MACRO-MOLECULES AND ACTIVITY OF PROTEASOME COMPLEX IN RAT SKELETAL MUSCLE

Abstract

389 It is well documented that regular exercise results in significant beneficial changes in health and quality of life, dispite of the paradox that exercise might induce free radical formation. Using rats of two age groups, we investigated the effect of nine week swimming (1hr/day, 5 times/wk) of moderate intensity on the oxidative status of phospholipids, proteins and DNA. The amount of thiobarbituric acid reactive substances and 4-hydroxynonenal protein adducts, reactive carbonyl derivatives (RCD) in general (measured by spectrophotometer) do not appear to differ in gastrocnemius muscle between exercised and control animals in two age-groups. On the other hand, the Western blot data of RCD revealed that the extent of carbonylation in a protein likely to be a carbonic anhydrase was smaller in exercised groups. Moreover, the amount of 8-hydroxydeoxyguanosine (8-OHdG) in nuclear DNA was also smaller in muscle of exercised animals. The activity of proteasome, a major proteolytic enzyme for oxidatively modified proteins, increased significantly in muscle of exercised rats. The activity of DT-diaphorase, the enzyme which induces antitumor quinones and related compunds, was markedly increased in exercised groups compared with sedentary. We suggest, that the regular exercise induced beneficial effects on health involves reduced accumulation of mutagenic 8-OHdG, increased activity of DT-diaphorase and proteasome complex, probably resulting in enhanced resistance against cancer and faster protein turnover.