Effect of corticotherapy on proteomics of endometrial fluid from mares susceptible to persistent postbreeding endometritis

Abstract

The objective was to determine the effects of corticotherapy, in the presence and absence of uterine inflammation, on proteomics of endometrial fluid from mares susceptible to endometritis. In 11 mares, estrus was induced seven times with 5 mg PGF(2α) given at 14-day intervals. The first estrus was a control (no treatment). During the third estrus, mares received glucocorticoid (GC) treatment (20 mg isoflupredone acetate) every 12 h, for three consecutive days. The fifth estrus was the Infected treatment (intrauterine infusion of 1 × 10(9) colony-forming unit/mL Streptococcus equi subspecies zooepidemicus). Finally, the seventh was a combination of GC + Infected treatment (infusion of bacteria 24 h after the first GC treatment). At 12 h after the end of each treatment, uterine samples were collected and submitted to two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) for protein separation and mass spectrometry. Both GC treatment and uterine lumen infection induced proteomic alterations in the endometrial fluid of susceptible mares, characterized by an increase, decrease, or both in the relative optic density and/or frequency of inflammatory acute phase proteins (APP), with major alterations occurring when corticotherapy was applied in the presence of an infectious process. Corticotherapy in the presence of infection increased α(1)-antitrypsin (AAT), transthyretin (TT), and actin, but reduced immunoglobulin G, whereas intrauterine infection increased haptoglobin (Hp) and apolipoprotein A-1 (ApoA-1) and decreased transferrin (TF). Infection reduced levels of α(1)-antitrypsin and transthyretin, whereas corticotherapy in the presence of infection increased their frequency. We concluded that GC influenced the immune response, not only as suppressors, but also as enhancers of local defense mechanisms, through an immunomodulatory action. Short-term corticotherapy could be beneficial for treatment of uterine infectious processes in the mare.

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.…”

“…Both proteins are considered as negative acute phase proteins (negative APPs), meaning their plasma concentrations decrease during acute inflammation (Khovidhunkit et al, ; Toussaint, Campbell, Piñeiro, & Gruys, ). However, in mares with intrauterine infection, the expressions of APOA1 and TF were opposing: APOA1 was increased while TF was decreased (Wolf et al, ). APOA1 is the major apolipoprotein on vertebrate high‐density lipoprotein (HDL) (Chapman, ).…”

“…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, ).…”

The preliminary studies on protein profile in retained and not retained foetal membranes in heavy draft mares

“…Wolf, Maslchitzky, Gregory, Jobim, and Mattos () examined protein profile of endometrial fluid of healthy mares and those suffering from endometritis. The authors described the alterations in the concentrations of acute phase proteins and the influence of corticoid therapy on this profile.…”

“…However, this publication does not cover placental tissues. Wolf, Maslchitzky, Gregory, Jobim, and Mattos (2012) The aim of this study was to analyse protein profile of the placentas from mares that developed foetal membrane retention in comparison with mares that had no retention. To address this task, we performed DIGE and liquid chromatography that served additionally for protein identification by mass spectrometry.…”