Factors affecting phagocytosis of bacteria by neutrophils in the mare’s uterus.

The research investigates the efficiency of bacteria cleanup by neutrophils, a type of white blood cell, in the uterus of mares susceptible and resistant to bacterial endometritis. The focus is on the process of opsonization, which enhances the ability of neutrophils to envelop and destroy bacteria.

Research Methodology

• The study involved ten mares, divided into two groups of five – those resistant and those susceptible to bacterial endometritis.
• An assay for chemiluminescence was used. This technique involves the measurement of light produced during chemical reactions as a way of evaluating different methods of opsonization and how they relate to the rate of phagocytosis.
• To measure the migration of proteins to the inoculated uterus, they used 123I-labelled albumin, a type of protein marker.
• The number of neutrophils migrating to the uterine lumen, the inside space of the uterus, were also determined.

Findings

• Before any inoculation, it was found that mares resistant to endometritis had substances in their uterine secretions that could opsonize bacteria, leading to successful phagocytosis.
• On the other hand, the uterine content of the susceptible mares could not effectively opsonize bacteria.
• Addition of serum to the uterine washings significantly improved the opsonization of bacteria in both groups.
• Differences between the resistant and susceptible mares were not observed in terms of serum protein migration or number of neutrophils moving to the site of contamination, in response to intrauterine challenge with pathogenic streptococci, a type of bacteria.
• However, after inoculation, the ability of the uterine contents to efficiently opsonize bacteria was found to be similar in the two groups.
• Subsequent clinical observations verified that the mares were indeed either resistant or susceptible to endometritis.

Conclusion

• The study found differences in the initial ability of neutrophils to effectively opsonize and destroy bacteria in mares resistant and susceptible to bacterial endometritis.
• However, following bacterial inoculation, both groups demonstrated similar capabilities of opsonization, suggesting that there may be additional factors at play that determine a mare’s resistance or susceptibility to endometritis.