PHYSICAL EXERCISE, OXIDATIVE STRESS AND MUSCLE DAMAGE IN RACEHORSES

Since it has been suggested that lipid peroxidation following free rad ical overproduction may be one of the causes of physical exercise-indu ced myopathies and hemolysis in horses, we looked for the possible rel ationships between these phenomena and muscle fiber damage. We use a h omogeneous group of Maremmana stallions which, after a 3-month trainin g period, underwent a series of physical exercises of increasing inten sity. We determined the contents of malondialdehyde (MDA), one of the main lipid peroxidation end-products, and glutathione the substrate of one of the most important free radical scavenger enzymes. We also mea sured creatine phosphokinase and serum lactate dehydrogenase isoenzyme activities whose modification may be indicative of muscle fiber damag e. The results obtained indicated that the physical exercise we adopte d was able to modify both MDA and glutathione contents in blood. Howev er, its effect on some LDH isoenzyme activities suggested possible dam age to tissues other than muscle. (C) 1998 Elsevier Science Inc. All r ights reserved.