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

Abstract

In vitro phagocytosis and chemotaxis of uterine and blood-derived polymorphonuclear neutrophils (PMNs) were compared in mares with different resistance to chronic uterine infection (CUI). Both the primary in vitro function of PMNs and the role of uterine environmental factors on PMN function were investigated. The uteri of mares susceptible to (n = 6) and resistant to CUI (n = 5) were inoculated with 5 x 10(6) Streptococcus zooepidemicus when the mares were in estrus. Uterine secretions in addition to uterine and blood-derived PMNs were sampled at 5 and 24 h later. During a subsequent estrus, bacterial inoculation of the uterus was repeated, and samples were removed from the mares 12 and 36 h later. Neither the phagocytic nor the chemotactic capacity of PMNs changed over time in any of the groups. However, chemoattractive properties of uterine secretions declined over time in both resistant (p < 0.0007) and susceptible mares (p < 0.01). Significantly higher phagocytosis (p < 0.03) and chemotaxis (p < 0.05) by uterine derived PMNs were found in the susceptible mares compared to resistant mares when a standardized opsonin (pooled plasma) was used. However, uterine secretions from susceptible mares demonstrated a poorer opsonizing capacity (p < 0.00002) but were more chemoattractant (p < 0.004) than secretions from resistant mares. When opsonins and chemoattractants were provided by plasma, no differences were detected in phagocytosis between blood-derived and uterine PMNs. In contrast, chemotaxis of uterine PMNs were superior to blood-derived PMNs in both resistant (p < 0.007) and susceptible mares (p < 0.0001) under these conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of corticosteroid therapy on the modulation of uterine inflammatory response in mares after artificial insemination with frozen semen

“…Troedsson et al (1993) observed that uterine activity is higher on the first 6 hours after breeding, and is maintained until 19 hours in resistant mares, but decreases to basal levels during this period in susceptible mares. According to Frean et al (1997), Yallampalli et al (1994) and Alghamdi et al (2005), the presence of nitric oxide promotes uterine relaxation and may contribute to a decrease in uterine clearance.…”

Equine seminal plasma reduces sperm binding to polymorphonuclear neutrophils (PMNs) and improves the fertility of fresh semen inseminated into inflamed uteri

“…At the time of semen collection, blood was collected from a healthy mare and PMNs were isolated as previously described (Troedsson et al 1993). Briefly, heparinized blood was subjected to centrifugation, the buffy coat was layered over a lymphocyte separation medium (Litton Bionetics, Kensington, MD, USA) and the PMNs were recovered from the buffy coat.…”

“…Five mares were inseminated with 1 £ 10 9 spermatozoa with at least 50% progressive motility and uterine secretion samples were collected 12 h later using cotton tampons as previously described (Troedsson et al 1993. The tampon was recovered by the use of a vaginal speculum and placed in a small, sterilized plastic bag to prevent evaporation.…”

Therapeutic considerations for mating-induced endometritis

“…Uterine defense mechanisms: Polymorphonuclear neutrophils (PMNs) are present in the uterine lumen within 30 minutes after mating (Katila,7995). Both bacterta and spermatozoa stimulate PMN-chemotaxis into the uterus (B/ue et al, 1984;Pycock and Allen, 1988;Troedsson et al, 1993a;Troedsson et al, 1995a) . Several mediators, including ?GFza are released during the course of the inflammation (Schalm, 1986).…”