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

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 less than 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.