Persistent mating-induced endometritis susceptibility: the role of uterine secretion

Abstract

This inflammatory reaction removes excess of semen and bacterial contamination inoculated at the time of breeding (Kotilainen et al. 1994, Fiala et al. 2007 SummaryThe aim of this study was to compare the protein profile of endometrial secretions from estrous mares resistant or susceptible to persistent post-mating endometritis (PPME). The hypothesis was that before insemination in susceptible mares the uterine environment is disturbed. Endometrial secretions from 17 estrous mares were collected before artificial insemination (AI), when a pre-ovulatory follicle and a characteristic ultrasonic uterine image from estrous was observed, using a regular vaginal tampon. Immediately after the remove of the tampon an endometrial biopsy was obtained. The biopsies were evaluated by immunohistochemistry. Another examination was performed 36-48h after AI to confirm ovulation and to detect intrauterine fluid accumulation (IUF). The mares were classified into 2 groups, according to the findings: "Resistant" (n = 11), no IUF was detected 36-48 h post AI and "Susceptible" (n = 6), mares presenting more than 2 mm of IUF 36-48 h after AI. An aliquot of endometrial secretions was centrifuged and the supernatant was transferred to cryovials for storage in liquid nitrogen until assay. The endometrial samples were recentrifuged and then submitted to 2D-PAGE using 12% acrylamide gels. Protein (100 mg) was loaded into the gels. Gels were stained in a 0.15% Comassie Brilliant Blue R-250. The Optiquant Acquisition & Analysis software was used to determine the relative protein content of the spots. The image analysis software identified 33 protein spots, with a molecular weight (MW) ranging from 15 to 105 kDa and isoeletric point (Ip) from 4.3 to 10.0. Twelve proteins showed higher relative protein content and eight proteins showed frequency differences in endometrial secretions from susceptible compared to resistant mares. Based on MW and Ip, the proteins may be related to inflammatory processes and uterine contractility. A higher (P = 0.07) estrogen and progesterone receptor staining intensity in stromal and luminal epithelium cells in susceptible mares was also observed. In conclusion, there is a difference in the uterine environment between resistant and susceptible mares to PPME, probably affecting the inflammatory response to spermatozoa. This difference can be related to ovarian steroid receptors expression.

Persistent post-breeding endometritis: effect of corticosteroid treatment on the number of protein bands from uterine endometrial fluid of susceptible mares

“…This increase may be explained by the presence of anti-inflammatory proteins (such as some anti-inflammatory cytokines), caused by the well-known potent corticosteroid anti-inflammatory action. Malschitzky et al (2008) observed higher optic density and frequency in 12 and 8 protein bands, respectively, in samples from susceptible mares, when compared to resistant mares. In 11 spots was possible to see a relationship with some proteins that have already been reported in horses, from which 6 may be involved in the inflammatory process.…”

Uterine infusion of conceptus fragments changes the protein profile from cyclic mares

“…Uterine fluid samples were collected using commercial vaginal tampons (Mini OB; Johnson & Johnson Industrial Ltd, São José dos Campos, São Paulo, Brazil). Tampons were aseptically introduced into the uterus, according to ( Reilas, 2001 ), modified by ( Malschitzky et al, 2008 ). The tampon was inserted through the cervix, protected by a palpation glove (double-glove technique).…”

Equine Reproduction: Seasonality, Endometritis, and Twinning in the Mare

“…It has long been proposed that mares are classified as either susceptible or resistant to PMIE. It has been shown that susceptible mares do have altered protein composition of their endometrial fluid [39] and these mares also exhibit higher levels of pro-inflammatory cytokines [40,41]. It has also been shown that these mares with a delayed uterine clearance have contractile defects of the endometrium, possibly contributing to this delay in uterine fluid clearance [42].…”