Comparative analysis of blood whole transcriptome profiles in Yili horses pre- and post-5000-meter racing

This study employed Yili horses participating in a 5000-meter race as a model to investigate exercise-induced gene expression alterations in peripheral blood using whole transcriptome sequencing. Jugular vein blood samples from the three leading horses were collected pre- and immediately post-race, yielding 2,171 differentially expressed mRNAs (2,080 upregulated, 91 downregulated), 4,375 differentially expressed LncRNAs (4,354 upregulated), and 68 differentially expressed circRNAs (64 upregulated). GO/KEGG analyses demonstrated significant enrichment of differential mRNAs in transmembrane transport function and pivotal signaling pathways (cAMP, MAPK, PI3K-Akt). Differential lncRNAs targeted neuro-signaling pathways (e.g., Neuroactive ligand-receptor interaction, Calcium signaling) and developmental regulators (stem cell pluripotency). Source genes of circRNAs were enriched in axon guidance and immune-related T cell receptor signaling. Molecular functions converged on transporter/receptor activity (mRNA/lncRNA) and nucleic acid/GTP binding (circRNA source genes). The protein-protein interaction analysis identified ten central genes within the heat shock protein family, such as <i>HSP90AA1</i> and <i>HSPA4</i>. Notably, significant upregulation of <i>HCN4, IGF1, PTHR1,</i> and <i>FGF23</i> indicated their potential roles in modulating cardiac rhythm, promoting tissue repair, and maintaining calcium-phosphorus homeostasis during exercise adaptation. This study provides comprehensive overview of transcriptomic regulatory mechanisms in the blood of Yili horses, offering a molecular framework for advancing understanding of physiological adaptation to exercise and optimizing equine exercise protocols.