Influence of Steroid Hormones on Uterineimmune Responses
The cyclical pattern of steroid hormone concentrations, characteristic for different stages of estrous cycle, regulates potential pathogenicity of micro-organisms that contaminate the uterus postpartum.
Steroid hormones influence functional activity of leucocytes migrating into uterus.
During estrogen phase of the ovarian cycle there is increased mucus production, and identified PMN activity;
During the luteal phase, there is reduced endometrial epithelial permeability to bacteria that delays leukocyte stimulation, and an absence of detoxifying agents in uterine secretions.
Inflammation of endometrium can occur following:
- Coitus,
- Artificial insemination (AI),
- More commonly in cattle after parturition,
- In majority of cattle,1-4 weeks after calving,
Micro-organisms contaminate the uterine lumen but self-cure usually occurs within 6 weeks postpartum. In those cows unable to eliminate infection, endometritis may develop subsequently.
Endometritis causes a significant delay in calving to conception intervals.
