Fig. 1

Experimental timeline (created with BioRender.com). Syngeneic female donor mice were primed with 5 IU of pregnant mare serum gonadotropin (PMSG; i.p.) to stimulate endometrial growth for 48 h before euthanasia. Immediately after euthanasia, uterine horns were isolated, minced (< 0.5 mm), washed with sterile phosphate-buffered saline (PBS), and resuspended in 1.0 ml of PBS to create a uterine tissue suspension. While recipient mice were anesthetized, a small dorsolateral incision (5 mm) was made, and 0.5 mL of tissue fragment suspension from a single uterine horn (Endometriosis group; experiment-1 n = 6–11/timepoint, experiment-2 n = 6) or sterile PBS only (Sham group; experiment-1 n = 6/timepoint, experiment-2 n = 6) was carefully injected into the peritoneal cavity of the recipient mice. Finally, the lesions, brains, and spinal cords were collected from recipient mice euthanized in estrus (based on vaginal smears) at ~ 4, ~ 8, ~ 16, and ~ 32 days after induction of endometriosis