Rat Model for Endometriosis (EM)

1. Randomly select one rat as a donor and euthanize it by cervical spondylolysis. Fix it in a supine position on the operating table, disinfect the abdomen with alcohol, and then cut open the abdominal cavity along the midline. Find the Y-shaped uterus, carefully pull out the left and right sides of the uterus, and carefully separate the bilateral uterine mesentery.

2. Detach the uterine horn and ovaries, cut the left and right uterus separately at the Y-shaped uterine bifurcation, and place them in a sterile curved disc containing physiological saline. Repeatedly rinse the blood stains on the surface of the uterus to further separate the remaining adherent uterine mesentery. Place two uterine horns in two sterile curved discs and cut them directly into equal sizes of approximately 1mm × 1mm fragments were suspended in physiological saline.

3. The uterus of the donor mice are implanted in the abdominal cavity of the recipient rat in a ratio of 1/4. One donor rat is supplied with endometrium to four recipient rat, and the tissue fragments in the curved disc were suspended with physiological saline.

4. Randomly select a rat as the recipient, and take the left lower abdomen at the midline below the umbilicus as the injection point. Inject physiological saline containing uterine tissue fragments into the recipient's abdominal cavity with a numbered needle, along with uterine tissue fragments, and then place it in the rat cage.

1. 4 weeks after surgery, ectopic lesion tissues are taken and observed under an optical microscope for morphology and histopathological results.
2. The model group rats have four regular estrous cycles, namely pre estrus, estrus, post estrus, and inter estrus, with each cycle lasting 4-5 days.
3. In the model group of rats, bulbous protrusions can be seen in the abdomen with naked eyes, showing cystic solidity and no activity. After cutting the skin, transparent bulbous cystic accretion can be seen, with a soft texture and clear liquid accumulation inside the capsule. Ectopic lesion tissue can be seen growing into a cavity like structure at low magnification under an optical microscope, while endometrial epithelial cells, stromal cells, and a small amount of glandular formation can be seen at high magnification. The histopathological manifestations are similar to those of human EMS.

SPSS software is used for statistical analysis, measurement data to mean ± standard deviation (x ±ｓ), using t test and single factor analysis of variance for group comparison , P<0.05 indicates there was a significant difference, P<0.01 indicates there are very significant differences.