Serum homocysteine and oxidative stress evaluation during exercise in horse.

The aim of the present work was to evaluate the influence of exercise on serum homocysteine and oxidative stress in Thoroughbreds during official races. For our study, ten Thoroughbred mares, 5 years old and clinically healthy, were used. The horses were trained to take part in an official 2100 meter race. Reactive oxygen species (dROMs), antioxidant barrier (Oxy-adsorbent), thiol antioxidant barrier (SHp) and homocysteine (sHcy) were investigated. Blood samples, collected from each horse at rest, immediately after the race, and 30 and 180 min after the end of the race, were collected by jugular venipuncture using vacutainer tubes with no additive for the assessment of dROMs, Oxy-adsorbent and SHp by means of a UV spectrophotometer, while serum total Hcy values were determined by high performance liquid chromatography with fluorimetric detection and isocratic elution. Statistical analysis, one way repeated measures analysis of variance (ANOVA), followed by Bonferroni's test, showed statistical differences (P<0.05 was considered statistically significant) for all parameters studied. Moreover, a coefficient of linear correlation (r) was computed for values of dROMs and sHcy for all sampling times but a significant linear regression (r = 0.94) was found only after the race. The variations of sHcy, dROMs, Oxy-adsorbent and SHp during the experimental period considered suggest the important role of oxidative status in the athletic horse. The systematic analysis of oxidative stress and its influence on homocysteine levels contribute to the clinical evaluation and assessment of the athletic performance of the horse.