The Effects of Treatment with N-Acetyl Cysteine on Clinical Signs in Persistent Breeding-Induced Endometritis Susceptible Mares.

This research investigates the effect of N-acetyl cysteine (NAC) treatment on clinical symptoms in mares prone to persistent breeding-induced endometritis (PBIE), a common cause of infertility. Although the study didn’t find NAC to improve clinical signs, it observed wider and more severe neutrophil infiltration in endometrial biopsies after NAC treatment, suggesting a need for further research.

Research Context

• Persistent breeding-induced endometritis (PBIE) is a prevalent issue causing infertility in mares. In PBIE, endometrial inflammation continues until embryonic descent, resulting in early embryonic death. Fertility complications arise due to poor endometrial biopsy grades (IIb or III), which are potential risk factors for PBIE.
• Clinical manifestations of PBIE include fluid accumulation in the uterus, abnormal endometrial edema, and high intrauterine neutrophil levels. Standard treatments primarily involve uterine lavage and oxytocin therapy.

Research Objective

• The study aims to explore the effects of N-acetyl cysteine (NAC) on PBIE. NAC, a mucolytic usually employed to address bacterial endometritis in mares, was chosen due to its anti-inflammatory properties.

Research Methodology

• A randomised, blinded, cross-over design clinical trial comprising PBIE-prone mares (n = 9) was conducted. The NAC treatment was given 12 hours prior to insemination.
• Endometrial cytology and biopsy samples were collected at 12 and 60 hours post insemination, then examined for inflammation. Transrectal ultrasound was used at 12 hours and every 24 hours post breeding to evaluate endometrial edema and intrauterine fluid volumes.
• The data obtained was analysed using repeated measures analysis of variance and the Mann Whitney Wilcoxon Test.

Results and Future Directions

• NAC treatment didn’t appear to improve the clinical signs in affected mares. However, increased diffuse and severe neutrophil infiltration was noted in endometrial biopsies taken from NAC treated mares.
• These results indicate that NAC may have an unstudied effect on inflamation in the endometrium of mares susceptible to PBIE, despite no observable clinical improvement. The study, therefore, suggests further research on a larger population to conclusively analyse the effects of NAC treatment on the endometrium of PBIE-susceptible mares.