Serum miR-155, miR-223, miR-17, miR-200a, miR-205, Interleukin 6, and Prostaglandins as Novel Diagnostic Markers for Endometritis in Arabian Mares

Background: So far the intimate link between serum microRNA (miRNA) and uterine inflammation in mares is unknown. We aimed (I) to investigate the expression profile of eca-miR-155, eca-miR-223, eca-miR-17, eca-miR-200a, and eca-miR-205 (II) and to measure the concentrations of interleukin 6 (IL-6), and prostaglandins (PGF2α& PGE2) in serum of Arabian mares with healthy and abnormal uterine status (endometritis).Methods and Results: This study was conducted on 80 Arabian mares; young (4-7 years), and old (8-14 years). These animals were divided into 48 sub-fertile including 16 young and 32 old mares suspected of endometritis and 32 fertile as control (24 young and 8 old) at stud farms. Serum samples were collected for measuring IL-6, PGF2α, and PGE2 concentrations, as well as serum miRNA isolation and qRT-PCR. Serum concentrations of IL-6, PGE2, and PGF2α were higher (P≤0.001) in mares with endometritis (young and old) compared to the control ones. Age of mares had a remarkable effect(0.001≤P≤0.01) onIL-6, PGE2, and PGF2αconcentrations. The relative abundance of eca-miR-155, eca-miR-223, eca-miR-17, eca-miR-200a, and eca-miR-205 was higher (P≤0.001) in both young and old mares with endometritis. We noticed that eca-miR-155, eca-miR-223, eca-miR-200a, and eca-miR-205 revealed higher (0.001≤P≤0.01) expression level in old than young mares with endometritis. Conclusions: To the best of our knowledge, this is the first study revealed that serum miRNA and serum inflammatory mediators (IL-6, PGE2, and PGF2α) could be used as non-invasive gold standard biomarkers, and therefore might be served as an important additional diagnostic tool for endometritis in Arabian mares.