Innate immune genes in persistent mating-induced endometritis in horses.

The research involves the study of immune response genes in horses prone to persistent mating-induced endometritis (PMIE), a condition that significantly reduces fertility. The project aims to note the expression of particular immune and effector genes in susceptible horses compared to a control group and the impact of the oestrous cycle stage on the expression. It was concluded that certain antimicrobial peptides showed increased expression in susceptible horses, thus revealing robust diagnostic markers for susceptibility to PMIE.

Research Objectives

• The main goal of this research was to determine the differences in the expression of selected immune response and effector genes in horses susceptible to PMIE compared to a healthy control group.
• The study also aimed to explore the effects of the oestrous cycle stage on the expression of these genes.

Methodology

• Endometrial biopsies from 18 uterine samples of control group horses and 16 PMIE-susceptible horses were analyzed using quantitative real-time reverse transcription-polymerase chain reaction.
• The researchers studied the expression of various immune-related genes involved in pathogen recognition and immune response like TLR2, NLRC5, TIMP1, CXCL 9, CXCL10, and CXCL11, and Uteroferrin.
• They also focused on genes for antimicrobial peptides including CCL2, sPLA2, lipocalin 2, lactoferrin, EBD1, LYZ, and SLPI.

Key Findings

• The expression of recognition receptor genes and certain chemokine ligand genes were found to be at similar levels both in the control group and PMIE-susceptible mares.
• The expression of genes corresponding to antimicrobial peptides (CCL2, sPLA2, lipocalin 2, and lactoferrin) was significantly higher in mares susceptible to PMIE compared to non-susceptible mares.
• Genes for antimicrobial peptides equine β-defensin 1 (EBD1), lysozyme (LYZ) and secretory leukoprotease inhibitor (SLPI) also had higher expression in susceptible mares. These genes can serve as robust diagnostic markers for susceptibility to PMIE.
• The diagnostic sensitivity of tests for EBD1, LYZ, and SLPI gene expression for detecting susceptibility to PMIE was high (100%, 94%, and 100% respectively), indicating these tests could be used for early and accurate diagnosis.
• When all three tests were positive, the specificity increased to 94%, with an overall sensitivity of 94%, indicating the robustness of these diagnostic markers.

Implications

• This study provides valuable insights into the pathophysiological changes in horses that are susceptible to PMIE.
• The identified diagnostic markers (EBD1, LYZ, and SLPI) have potential applications in the diagnosis and treatment of PMIE, potentially improving horse fertility.