Oxidative stress by physical exercise induces a lipidic peroxidation reaction in cellular membranes and damages in proteins and nucleic acids. Malondialdehyde (MDA) is one of the final products of this reaction. Erythrocytic reduced glutathione (GSH), a multifunctional antioxidant, is present in the plasma and erythrocyts and it represents the total antioxidant suitability of the organism after an oxidative stress. The aim of this study was to evaluate the oxidative stress in different physical exercise conditions through serum MDA and erythrocytic GSH measurement in 45 American Trotter and crossbred horses distributed in three groups: G1 (no physical exercise), G2 (until 6 months of regular physical exercise) and G3 (more than 12 months of regular physical exercise). In the animals with no physical exercise MDA values were lower than the others. There was no difference in GSH values corrected by hemoglobin (Hb) or hematocrit (VG) values among the groups. However, there was a tendency of greater values in G2, where their antioxidant system is adapting to the regular physical exercises and their consequent damages. We conclude that physical exercises induce cellular damage by oxidative stress, but the antioxidant system keeps the homeostasy and it is capable to adapt itself to the free radicals harm.
Oxidative stress; malondialdehyde; erythrocytic reduced glutathione; equines; physical exercise
