Inflammatory mechanisms of endometritis

Abstract

Transient post breeding endometritis is a normal physiological reaction in the mare, as it is believed that an inflammatory response is necessary for the effective removal of contaminating bacteria and excess spermatozoa introduced into the uterus. While most mares can clear endometritis within a reasonable amount of time, persistent endometritis caused by either bacteria or spermatozoa can threaten the success of a pregnancy. A subpopulation of mares is susceptible to persistent endometritis, and these mares are a concern in equine reproductive medicine. Research has identified several factors that contribute to susceptibility; however, the exact mechanisms of the progression of the disease are still being elucidated. Current research focuses on endometrial gene expression during endometritis in an attempt to understand the timing of specific inflammatory processes involved with the development of susceptibility to persistent endometritis. With an increased understanding of the mechanisms involved with the disease, current treatments can be improved upon, and new treatments can be developed to target affected pathways.

Grand Challenge Animal Reproduction-Theriogenology: From the Bench to Application to Animal Production and Reproductive Medicine

“…The main species that have benefited from such techniques are small animals, equine, and camelid. The combination of established techniques such as endometrial biopsy, culture, and cytology with molecular techniques has allowed substantial advances in our understanding of the pathophysiology of endometritis and led to the development of methods for diagnosis, prevention, and treatment (74, 75). …”

Neuropharmacologic Approaches to Restore the Brain’s Microenvironment

“…Well known is the fact that MP can cause BBB breakdown following brain inflammation, migrating toward the inflammation site via processes known as diapedesis and chemotaxis (Woodward and Troedsson 2015). Relying on the natural inflammatory responses, macrophages have been widely applied for the active delivery of therapeutic agents, including nucleic acids, peptides, drugs and enzymes, to the brain.…”

Infection and Infertility in Mares

“…This "susceptible" mares have a delay in uterine clearance, and the inflammatory products accumulate as uterine fluid. Such mares have a reduced pregnancy rate due to an inappropriate environment for the early development of the embryo [34]. However, the reproductive tract of mare possesses various mechanisms to protect itself against infection: physical barriers as vulva, vestibulovaginal sphincter, and cervix, local immune mechanisms and the physical ability to eliminate products of inflammation, as described below.…”

“…The response to endometritis is mediated by inflammatory mediators such as leukotriene B4 (LTB4) and prostaglandins (PG) E2. Mares susceptible to endometritis have a higher expression of pro-inflammatory cytokines (interleukin-1 β-I; L-1β), IL-6, and tumor necrosis factor-α (TNF-α) during estrus and IL-1β and TNF-α during diestrus [24,34]. An overregulated endometrial gene expression of pro-and anti-inflammatory cytokines (IL-1β, IL-6, IL-8) and a systemic acute phase response (APR) have been described in mares with experimentally induced E. coli endometritis [40], as it has gene expression of cytokines in response to AI with dead spermatozoa in resistant and susceptible mares [24,36].…”

“…Chronic degenerative endometritis or endometriosis is degenerative change that occurs in older mares or following repeated inflammation of the uterus. Degenerative fibrosis can be the result of normal aging processes or may be the end-product of a life of continuous reinfection: anyway, healing uterine mucosa causes infertility in older mares [34]. Problems related to weaken reproductive structures can cause urinary retention, a condition in which the mares do not empty completely urine, especially during estrus.…”