Paiva et al. data

We aimed in this study to evaluate the impact of intrarectal ozone therapy on haematological and biochemical parameters, as well as the pain induced by the procedure in sport horses. Twelve Quarter Horses (three males and nine females) used as their own controls to assess the effects of ozone therapy. Blood samples were collected before treatment (Control), 24 hours after ozone treatment (24-h post ozone therapy), and seven days after the last day of ozone therapy (7-days post ozone therapy). These samples were analysed for haematological and biochemical parameters. Pain assessment, clinical evaluation, and the measurement of heart rate (HR) and respiratory rate (RR) were conducted before and during ozone therapy. Ozone therapy significantly affected haemoglobin (F2,20=5.55; P=0.012), mean corpuscular haemoglobin concentrations (MCHC) (F2,20=16.01; P<0.001), and serum aspartate aminotransferase (AST) activity (F2,20=20.49; P<0.001). Specifically, haemoglobin concentration decreased 24 hours after ozone therapy, MCHC levels increased seven days post-ozone therapy, and serum AST activity decreased seven days post-ozone therapy. Blood smears taken 24 hours post-treatment revealed red blood cells with membrane deformities, which normalised by seven days post-treatment. None of the animals exhibited clinical symptoms, although pain scores increased (before: 4.2±0.4; during: 5.3±0.4; F1,107=5.20; P=0.025). The reduction in haemoglobin was likely due to oxidative damage, which stimulated the production of erythrocytes with higher haemoglobin content. Lower AST levels suggested an absence of liver damage. The increase in pain scores suggests that using lower concentrations or doses in future studies might alleviate discomfort in the animals.