Endometrial nitric oxide synthase activity in mares susceptible or resistant to persistent breeding-induced endometritis and the effect of a specific iNOS inhibitor in vitro.

The research article is a study on the role nitric oxide system plays in persistent breeding-induced endometritis in mares. Scientists found a difference in nitric oxide synthase activity between mares susceptible or resistant to this condition, and demonstrated the inhibitory effect of a specific nitric oxide synthase inhibitor on endometrial activity in vitro.

Research Objective

• The primary objective of this research study was to explore the difference in the total activity of nitric oxide synthase (NOS) in the endometrium between mares that are resistant or susceptible to persistent breeding-induced endometritis (PBIE). It also aimed to determine the impact of a particular inducible nitric oxide synthase (iNOS) inhibitor on endometrial NOS activity in vitro.

Research Methodology

• The researchers selected six mares that were resistant to PBIE and six which were susceptible based on well-defined criteria, and the result of an intrauterine challenge with killed spermatozoa during oestrus.
• After the challenge, endometrial biopsy samples were procured from the mares and cultured in medium supplemented with L-arginine with or without an iNOS inhibitor.
• The culture medium and the endometrial tissues were collected and analyzed for NO and total protein respectively, 24 hours after culture.
• The endometrial NOS activity was determined by normalizing the total NO content of the medium with the wet weight or total protein of the endometrial tissue.
• Non-parametric tests were deployed for statistical analysis.

Key Findings of the Research

• Mares that were susceptible to PBIE showed significantly higher endometrial NOS activity than those resistant to the condition.
• The iNOS inhibitor treatment considerably lowered NOS activity in endometrial samples from both susceptible and resistant mares.

Significance of the Research

• The research concludes significant differences in endometrial NOS activity between mares susceptible and those resistant to PBIE.
• It also provides a platform for in vivo testing of specific iNOS inhibitors, which could be further explored as preventative or therapeutic options for PBIE in mares.