Influence of Cavalcade of Different Distances on the Serum Concentrations of the Cardiac Biomarkers Troponin I (Ctni) and Creatine Kinase Myocardial Band (CK-MB) in Horses

Abstract

Cardiac biomarkers are potentially useful to identify primary or secondary cardiac muscle damage in horses and higher values of cardiac troponin have also been seen after high intensity exercise. The objective of this study was to investigate the effect of cavalcade of different distances on the serum concentrations of cardiac troponin I (cTnI) and creatine kinase myocardial band (CK-MB) in Mangalarga Marchador horses. Fifteen clinically normal geldings (age 6.2 ± 1.2 years, weight 420 ± 58 kg) were distributed into three groups of five animals each. The groups were submitted to cavalcade along 4 km (G4), 8 km (G8), and 20 km (G20) at mean speeds of 15 km h -1 , 12 km h -1 , and 12 km h -1 , respectively. From each horse, blood samples were collected after and post-exercise. Serum cTnI and CK-MB concentrations were determined with a solid-phase chemoluminescence immunoassay. The assay has an analytical sensitivity of 0.02 ng mL-1. The concentration of blood lactate was analyzed using an i-STAT portable clinical analyzer. After exercise, increases (P < 0.01) in cTnI and CK-MB concentrations were observed in G4 and G8. No changes (P > 0.05) in lactate concentration were observed post-cavalcade in all groups. Power tests values were 1.0 for cTnI and CK-MB, 0.63 for lactate. Positive correlations (0.4 < r < 0.5) were observed between cTnI and CK-MB. The changes in cTnI and CK-MB concentrations post-exercise is indicative of myocardial cell injury in healthy Mangalarga Marchador horses, which could be considered as an adaptation to physical exercise.