The Effect of Immune Modulators on Endometrial Cytokine Expression in Mares Susceptible to Persistent Breeding Induced Endometritis

Persistent breeding induced endometritis (PBIE), is a leading reproductive health concern in horses. Treatment strategies aimed at modulating the innate immune response are available, but the mechanisms of action are not well described. The objective of this study was to evaluate the effects of treatment with three immunomodulators: (1) dexamethasone, (2) mycobacterial cell wall extract (MCWE) and (3) platelet rich plasma (PRP) on the endometrial innate immune response in mares susceptible to PBIE. We hypothesized that these treatments alter uterine NO production and the mRNA expression of IL1B, IL6, IL10, IFNG, IL1RN, and iNOS when compared to non-treated susceptible mares. In the first experiment, artificial insemination (AI) was performed in six mares susceptible to PBIE during three consecutive estrous cycles with 1 × 109 killed spermatozoa 1) alone (control), or in combination with 2) dexamethasone (50 mg iv) at the time of AI, or 3) with MCWE (Settle™, 1.5 mg iv) administered 24 hours prior to AI. Uterine secretions were collected six hours after AI using a sterile tampon, and a 200 mL lavage was used to collect remaining secretions. [...]