Establishment of endometriosis model in allogeneic Sprague-Dawley rats

Objective To explore the feasibility of the establishment of endometriosis (EMS) model in allogeneic rats by abdominal subcutaneous implantation. Methods Choose 48 healthy, unmated and in estrus (normal estrous cycle ≥ 2) female Sprague-Dawley (SD) rats as the research object. According to random number table, 48 SD rats were divided into donor rats (n=24) and recipient rats (n=24). When the SD rats in estrus, we sutured the donor rats uterine tissue to the abdominal subcutaneous of recipient rats, and removed the ectopic lesion tissue 3 weeks after surgery, then observe histopathologic findings under an optical microscope. Results All of those 48 SD rats had regular estrous cycles, there were 4 estrous cycles which were proestrus, estrus, metestrus, and diestrus, each period lasted 4-5 d. Twenty-four SD rats (recipient rats) were alive, the successful rate of allogeneic abdominal subcutaneous implantation of SD rats was 66.7%(16/24), in which 16 SD rats' abdomen could see dome projection, which was cystic and solid, non-active, and cut the skin open, we can see translucent dome cystic proliferator, texture soft, clear liquid accumulation in the capsule. The average volume was (34.5±19.8) mm3. Ectopic lesion tissue was observed through low magnification optical microscope (×100), and we could see ectopic lesions grew into a cavity-like structure. Through we could see endometrial epithelial cells, stromal cells and the formation of a small amount of glandular under high magnification optical microscope (×400). Tissue pathology was similar to human EMS. Conclusions The tissue pathology changes of ectopic endometrial in EMS model of allogeneic SD rats by subcutaneous transplantation were similar to human EMS, EMS SD rats model can be used in the studies on EMS. Key words: Endometriosis; Models, animal; Transplantation, homologous; Rats