Importance of Induction Endometritis and Vaginal Cytology in Rat Model: A Narrative Review Article

Endometritis is a female reproductive disease characterized by the inflammation of the endometrial glandular and stromal tissues. It is usually occurred due to uterine contamination with infectious causes. Animal models of clinical endometritis are very important to prevent the incidence and treatment of endometritis. Vaginal cytology method is considered as a golden standard for determining the estrous cycle stage in female rats. The aim of this study was to induce endometritis in a rat model and determine the stages of the estrous cycle of this animal using vaginal cytology method in order to successfully induce this condition in this animal model.

Inflammation changes the production of endometrial cytokines, which may result in menstrual disorders and decreased endometrial reception by impaired endometrial tissue dysfunction. Increased expression of specific cytokines genes such as IL-6, IL-8 and TNF-α can be used to detect the severity and degree of endometritis. Uterine infections are known as a result of damage to the defense mechanisms of the uterine tissue, which are caused by physiological changes in the postpartum period. Another change that occurs in the postpartum period is the increase in the production of reactive oxygen species. The imbalance between the production of reactive oxygen species and its clearance leads to the creation of oxidative stress conditions. On the other hand, there is a significant relationship between inflammatory diseases such as endometritis and oxidative stress. On other hand, by accurately determining the estrous cycle of rats by using vaginal cytology, endometritis can be well induced in this species.