Inflammatory components in uterine fluid from mares with experimentally induced bacterial endometritis

Abstract

Summary Exudate and uterine flushings were collected at either 30, 60, 120 or 240 mins after intrauterine infusions of Streptococcus zooepidemicus in genitally normal mares during oestrus. Uteri were also flushed without prior induction of endometritis. Protein concentrations in exudate and flushings increased with time and exudate pH decreased with time; the pH of flushings did not alter. Lysozyme and lactate dehydrogenase were present in flushings from non‐infected uteri, but concentrations increased with time after infection. Immunoreactive prostaglandin E2 was undetectable before infection, but concentrations rose after infection. No neutrophils were present in non‐infected flushings but, by 30 mins, there were significant (P<0.01) neutrophil numbers in exudate and flushings; thereafter numbers increased, particularly in exudate. Acute endometritis resembled acute inflammation at other sites in the horse and a significant response had occurred by 30 mins after experimental infection.

Function of Uterine and Blood-Derived Polymorphonuclear Neutrophils in Mares Susceptible and Resistant to Chronic Uterine Infection: Phagocytosis and Chemotaxis1

“…This occurs as a result of the bypassing by the stallion's penis of all the physical barriers that normally protect the uterus from contamination. For the uterus to avoid a persistent infection, the mare must be able to launch a local immune response, the importance of which has been emphasized by identification of both humoral [3][4][5][6][7][8] and cellular [9][10][11][12][13] components in the uterus.…”

Uterine fluid from bitches with mating-induced endometritis reduces the attachment of spermatozoa to the uterine epithelium

“…The present work indicates that fluid which persists after mating could have an important effect in reducing the attachment of spermatozoa to the uterine epithelium and that this is largely mediated by PMNs. However, while the role of PMNs is clearly important in this study, this did not fully explain the reduced attachment of spermatozoa to the uterine epithelium post-insemination in bitches with uterine fluid; information from other species would suggest that some effect might be associated with bacterial or inflammatory components of the uterine fluid Pycock and Allen, 1990;Nash et al, 2010). Interestingly, previous work in the bitch demonstrated that the administration of oral antibiotics post-mating to bitches with endometrial hyperplasia and presumed matinginduced endometritis could increase pregnancy rate, but not litter size (England et al, 2012a,b).…”

“…In the mare, where mating-induced endometritis is common and is inevitably characterised by persistence of uterine fluid after mating , the postmating fluid contains large numbers of PMNs, as well as inflammatory mediators and commensal bacteria Pycock and Allen, 1990;Nash et al, 2010). It is clear that the concentration of PMNs found after normal mating can reduce the attachment of spermatozoa to the uterine epithelium, because the spermatozoa become attached to PMNs (England et al, 2012a).…”

Immunoglobulin (IgG and IgA) and complement (C3) concentrations in uterine secretion following an intrauterine challenge of Streptococcus Zooepidemicus in mares susceptible to versus resistant to chronic uterine infection1

“…Both IgG and C3 declined during this time, which may be explained by active opsonization of bacteria. A rapid migration of PMNs into the uterine lumen in response to a uterine infection has been reported by Watson et al [16] and by Pycock and Allen [23]. Optimal function of PMNs requires opsonization of the infectious agent before it can be phagocytized and killed.…”