Effect of ovarian hormones on promotion of bactericidal activity by uterine secretions of ovariectomized mares

Abstract

The bactericidal and phagocytic activities of blood neutrophils suspended in uterine washings and the mobilization of neutrophils into the uterine lumen were studied in ovariectomized mares receiving oestradiol benzoate (N = 4), progesterone (N = 4) or oily vehicle (N = 4). Uterine lavage was performed sequentially up to 144 h after induction of endometritis by intrauterine infusion of glycogen (1%). There was no significant difference between the 3 groups in speed of mobilization of neutrophils into the uterus in the first 6 h after infusion but there were significantly more uterine luminal neutrophils in progesterone-treated than in oestradiol-treated mares by 24 h after infusion (P less than 0.01). Uterine washings collected from progesterone-treated mares at 0, 24 and 144 h were significantly worse at promoting bactericidal activity by neutrophils than washings from oestradiol-treated and control mares (P less than 0.001). In oestrogen-treated and control mares bactericidal activity had increased by 144 h but in progesterone-treated mares bactericidal activity remained low. Neither treatment nor time affected the ability of washings to opsonize yeast blastospores. Elevated concentrations of progesterone in plasma were therefore associated with decreased bactericidal activity of neutrophils suspended in uterine washings but the generation of C3b in washings did not appear to be affected by hormone treatment.

Preimplantation factor modulates acute inflammatory responses of equine endometrium

“…Therefore, PIF may interact with the native steroid milieu of endometrium; endogenous progesterone promotes immune‐suppression but concentrations are low during the follicular stage (Watson et al . ). Neither PIF alone (either 50 or 100 nmol/L) nor PIFscr caused an increase of PGF 2 α compared to controls in explants derived from all stages of the oestrous cycle, demonstrating that PIF itself did not inadvertently cause inflammation, at least in terms of prostaglandin response.…”

Influence of administration of ovarian steroids on the function of neutrophils isolated from the blood and uterus of ovariectomized mares

“…In another study, however, which investigated the speed of mobilization of neutrophils into the uterine lumen, there was no significant difference in the first 6 h after induction of uterine inflammation between ovariectomized mares treated with progesterone, oestrogen or vehicle (Watson, Stokes, David & Bourne, 1987c). More detailed studies are therefore required to understand the complex cellular inter¬ actions with ovarian hormones and their effect on disease resistance in the mare.…”

Effect of ovarian steroids on migration of uterine lumenal neutrophils and on chemokinetic factors in uterine secretions from mares

“…The chernotactic properties of equine uterine secretions in vitro have been investigated and no significant differences were observed in neutrophil migration towards lavage fluids collected during oestrus or dioestrus (Blue, Blue, Kenney and Merritt 1984;Strzemienski, Do and Kenney 1984). These results were supported by work performed in vivo, in which ovarian steroids did not influence rate of rnobilisation of neutrophils into the uterine lumen in the first 6 h following induction of endometritis (Watson, Stokes. David and Bourne 1987a).…”