Effect of the estrus cycle stage on the establishment of murine endometriosis lesions

Abstract

Background:Establishment of a standardized animal endometriosis model is necessary for evaluation of new drug effects and for explaining different ethological aspects of this disease. For this purpose, we need a model which has more similarity to human endometriosis.Objective:Our objective was to establish an autologous endometriosis mouse model based on endogenous estrogen level and analyze the influence of estrus cycle on the maintenance of endometriotic lesions.Materials and Methods: In this experimental study, endometriotic lesions were induced in 52 female NMRI mice by suturing uterine tissue samples to the abdominal wall. The transplantation was either performed at proestrus/estrus or at metestrus/diestrus cycles. Urine-soaked beddings from males and also male vasectomized mice were transferred to the cages to synchronize and maintenance of estrus cycle in female mice. The mice were sacrificed after different transplantation periods (2, 4, 6 or 8 wk). The lesions size, macroscopic growth, model success rate, histological and immune-histochemical analyses were assessed at the end.Results:From a total of 200 tissue samples sutured into the peritoneal cavity, 83 endometriotic lesions were confirmed by histopathology (41.5%). Model success rate for proestrus/estrus mice was 60.7% vs. 79.2% for metestrus/diestrus mice. The endometriotic lesions had similar growth in both groups. Number of caspase-3, Ki67-positive cells and CD31-positive micro vessels were also similar in endometriotic lesions of two groups.Conclusion:If we maintain the endogenous estrogen levels in mice, we can induce endometriosis mouse model in both proestrus/estrus and metestrus/diestrus cycle without any significant difference.

In vivo effects of AZD4547, a novel fibroblast growth factor receptor inhibitor, in a mouse model of endometriosis

“…The essential role of estrogen for the maintenance of the disease but not for the initiation of the disease was proved in other studies conducted on mice and monkeys 22‐24 . In 2018, Kiani et al demonstrated the maintenance of the endogenous estrogen levels in mice as the only necessary requirement for the development of endometriosis, with no significant difference between the stages of the estrous cycle 25 …”

Induction of the Mice Model Regarding the Endometriosis and Assessment of Antioxidant Treatment Effectiveness: An Experimental Protocol

“…4. Histologically, the implants were scored based on a semi-quantitative assessment as follows (19)(20)(21).…”

New rat to mouse xenograft transplantation of endometrium as a model of human endometriosis

“…Thus, it seems that isolation of the endometrium from the two other layers of the uterus (myometrium and perimetrium) can probably model human endometriosis conditions more closely. 6 Endometrium in mice is a thin microscopic layer that is often impossible to dissect out, and besides the endometrium is a fragile tissue which cannot be sutured. However, the endometrial layer in the proliferative phase of of the estrous cycle is thick enough to be dissected and transplanted.…”