*3.1. Methods Used in the Studies Reviewed*

3.1.1. Experimental Studies: Methods to Induce and Evaluate Endometriosis

In experimental studies, endometriosis is induced in mice with transplantation of endometrial fragments in the peritoneal cavity by autologous or heterologous transplantation of the uterine horns. The endometrium-rich fragments are obtained by removing the uterine corn from the donor or through minor surgery to collect endometrial tissue and transplant it in the same animal. The fragments are injected or implanted in the recipient animals' peritoneal cavity. The animals have randomly grouped accordingly: those submitted to endometriosis that received treatment, those submitted to endometriosis without treatment and a control group not submitted to experimental endometriosis. Following the treatment with the respective mediator, the mice are sacrificed or re-operated to assess the lesions and collect the tissue to measure the intervention effects [7,19,26,28,29,32,35,40,41].

Some studies have also carried out hormonal stimulation of endometrial lesions with estrogen administration [29] or estrogen and 17-OH-progesterone [26]. In Tomio et al. investigation, donor and recipient were oophorectomized and stimulated with estrogen [31]. In addition, researchers have used vaginal cytology in mice to define its estrous cycle stage [27–29,41]. Further, Dmitrieva et al. injected Evans Blue dye to assess leakage in endometrial lesions and implant a telemetric probe to analyze vaginal nociception in mice [30].
