Integrative Analysis of miRNA in Circulating Leukocytes of Quarter Horses Before and After Exercise

• Grant number: 25/19944-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2025
• End date: October 31, 2026
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: Juliana Regina Peiró
• Grantee: Fernanda Ferrabotti de Oliveira
• Host Institution: Faculdade de Medicina Veterinária (FMVA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

Due to the similarity between certain systems and organic responses, the horse is used as an experimental model for several human diseases, such as asthma, in the characterization of immune system responses and locomotor disorders. The use of the equine species as an experimental model is not limited to the study of diseases but is also applied in the evaluation of responses to exercise. Being a natural athlete, understanding the molecular mechanisms of exercise-induced stress is of fundamental importance in planning an adequate training program to achieve better performance while preserving the animal's health.The rapid acceleration of the Quarter Horse and the fact that it is the fastest breed over short distances make it superior in short-duration competitions. In barrel racing, the best horses usually complete the course in about 18 seconds, a period sufficient to induce a substantial increase in lactatemia, accompanied by a decrease in pH and bicarbonate concentrations in the blood. Although metabolic responses and exercise adaptations have been well documented, the cellular and molecular mechanisms are still not fully understood. In both humans and horses, short sessions of high-intensity exercise induce a substantial increase in circulating leukocytes, which play a role in tissue repair, muscle growth, and other key processes in the organism.Significant gene expression changes after short-term exercise in humans have been detected between two and eight hours in muscle, and immediately after and up to four hours in peripheral blood. Marked changes in the gene expression profile of circulating leukocytes can occur rapidly during exercise in both humans and horses. Studies showing changes in circulating miRNA (c-miRNA) expression during exercise are recent, and some have already been identified as potential biomarkers, both to evaluate response and adaptation to exercise and to determine the conditioning level in humans. The global miRNA profile has also been identified in different healthy equine tissues. The present study is justified not only because of the economic importance of horses in our country and in the world of equestrian sports but also because horses have been used as experimental models for several human disorders.