DNA damage in leukocytes of equines subjected to physical effort

Abstract

In recent years there has been a growing interest in the study of the beneficial and harmful effects associated with exercise. The aim of this study was to establish the existence of DNA damage in circulating leukocytes of horses undergoing high intensity and short term physical activity by using the alkaline comet assay. Five horses subjected to a standardized exercise test were used. Samples were collected before starting the exercise, at the point of reaching maximal speed, at the end of the test and 30 days post exercise. Simultaneously, oxygen consumption during the exercise test was measured. The relative frequency of cells with DNA damage was 0.122, 0.240, 0.210 and 0.100, respectively. DNA damage index was 11,8, 28,4, 23 and 10,4 UA, respectively. Significant increases were observed from baseline time and 30 days after exercise when the animals reached maximum speed and at the end of the exercise (p< 0.05). These results suggest that genotoxic damage inducing factors occur mainly during physical fatigue, and that this is probably due to oxygen free radicals.