Proteomics of endometrial fluid after dexamethasone treatment in mares susceptible to endometritis

Abstract

Corticotherapy is a common treatment in mares susceptible to endometritis. Isoflupredone improves pregnancy rates and affects the protein profile of endometrial fluid in comparison to untreated mares. Dexamethasone decreases postbreeding fluid accumulation and uterine edema; however, its effects on the protein profile of the endometrial fluid have not yet been studied. The aim of the present study was to verify the effect of dexamethasone on the protein profile of endometrial fluid, in the presence or absence of infection, from mares susceptible to persistent postbreeding endometritis. Nine susceptible mares aged between 7 and 18 years were used. After checking for signs of estrus, mares were subjected to four treatments: C: mares received no treatment and served as control; D: mares received 40-mg dexamethasone at breeding, with collection of samples after 6 hours; I-6 and I-24: intrauterine infusion of 1 × 10(9)Streptococcus zooepidemicus/mL and samples collected after 6 and 24 hours; I/D-6 and I/D-24: intrauterine infusion of 1 × 10(9)S zooepidemicus/mL and 40-mg dexamethasone, collecting the sample after 6 and 24 hours. All mares were subjected to all treatments. Samples were collected and subjected to two-dimensional electrophoresis and mass spectrometry for the identification of relevant protein spots. Corticotherapy altered the protein profile of the endometrial fluid of susceptible mares, characterized by an increase and/or decrease in the optical density of inflammatory acute-phase proteins. We conclude that the use of dexamethasone in mares with and without infection alters the protein profile of endometrial fluid of susceptible mares.

A comparison of the uterine proteome of mares in oestrus and dioestrus

“…We recognize that our ability to identify significant differences for other identified proteins was limited by the small number of mares in the study and the overabundance of some proteins in these flush samples. The availability of mares meeting our endometritis exclusion criteria was a limiting factor, but the sample size of the current study is comparable to previous studies on uterine proteomics in mares (Arlas et al, ; Smits et al, ; Wolf et al, ). Depletion of abundant proteins can improve sensitivity of proteomic analysis and might become useful for some low‐abundance proteins that have diagnostic application.…”

“…The study indicated a differential expression of 119 proteins around the time of MRP in mares, including upregulation of several inhibitors of prostaglandin synthesis. Changes in the uterine fluid proteome have also been reported after corticotherapy in mares with endometritis (Arlas et al, ; Wolf, Maslchitzky, Gregory, Jobim, & Mattos, ).…”

Persistent Breeding-Induced Endometritis in Mares—A Multifaceted Challenge: From Clinical Aspects to Immunopathogenesis and Pathobiology

“…A reduction of pro-inflammatory IL1β, CXCL8, and SAA and suppression of inflammatory mediators, such as COX-2, lipo-oxygenase 5, and NO, were reported after dexamethasone therapy, while an increase in the inflammatory modulating and anti-inflammatory IL6, IL10, and IL1RN was also observed after treatment [33]. Additionally, the administration of dexamethasone altered the production of acute-phase proteins following bacterial challenge [295] and did not alter the phagocytic function of blood-derived PMNs [296], which could predispose the mare to a secondary infection. This alteration in the acute phase protein profile has also been noted following treatment with prednisolone [297].…”

Non-antibiotic treatment of equine endometritis

“…However, mares with a history of excessive post-breeding inflammation had significantly higher pregnancy rates when treated with acetate 9-a-prednisolone (0.1mg/kg) twice daily when compared to control cycles (Dell'Aqua et al 2004). An effect of corticosteroids on the innate uterine immune response as well as the uterine environment has been reported by several authors , Arlas et al 2015. Although the immune modulation appears to favor resolution of inflammation, it does not mimic that of resistant mares.…”