Evaluation of oxidative stress in healthy horses undergoing ozone therapy by rectal insufflation in decreasing doses

• Grant number: 21/06719-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2021
• End date: August 31, 2022
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: Breno Fernando Martins de Almeida
• Grantee: Laryssa Eduarda de Campos Lopes
• Host Institution: Centro Universitário Faculdades Integradas de Ourinhos. Fundação Educacional Miguel Mofarrej. Ourinhos , SP, Brazil

Abstract

Ozone therapy causes controlled oxidative stress, improving antioxidant, immune, and circulatory responses, which seems to help in infectious and inflammatory processes, second reports. Still, little is known about how ozone therapy systemic oxidative stress parameters, especially in horses. This assessment is necessary to understand the pathophysiological mechanisms that ozone therapy causes on organisms, an initiative to evaluate the security of this therapy. In this context, this project aims to assess the oxidative stress parameters of healthy equines subjected to ozone therapy by rectal insufflation, in addition to the assessment of clinical, hematological, and biochemical parameters. For this, 10 adult healthy mares will be submitted to 8 applications of ozone by rectal insufflation two times per week at 0.2 (week 1), 0.15 (week 2), 0.10 (week 3), 0.05 (week 4) mg of ozone/kg. Blood samples for the evaluation of oxidative stress, complete blood count, and biochemicals will be collected 10 weeks after the start of therapy. Additionally, another 10 healthy mares will constitute the controlling group and blood samples will be obtained at the same moments of the treated group. Oxidative stress will be determined by total antioxidant capacity (TAC) using four methods: ABTS cation reduction (TAC-ABTS), ABTS cation reduction associated with peroxidase (TAC-ABTS+HRP), ferric reducing antioxidant power (TAC-FRAP), and cupric ion reducing antioxidant capacity (TAC-CUPRAC); determination of the total oxidant capacity (TOC), lipid peroxidation the thiobarbituric acid reactive substances (TBARS) and two antioxidants uric acid and albumin. Hematological and clinical biochemical analyzes will be performed in an automated veterinary cell counter and in a semi-automated photocolorimeter using a set of commercial reagents, respectively. Variables will be tested for normality and homoscedasticity and the differences between moments will be verified by repeated-measures ANOVA with Tukey's post-test or Friedmann with Dunn's post-test, while the differences between the groups in each moment will be verified by paired t or Mann-Whitney tests, being considered significant when p<0.05. (AU)