Establishment and evaluation of an opening-method model of endometriosis in rats

Objective To research the reliability,evaluation index and achievement ratio of an opening-method model of endometriosis in rats compared with the transplanting-method.Methods Female virginal rats were operated on with the opening-method(the left side of the uterus) and transplanting-method(the right side of uterus).In the left side of the uterus,the endometrium was stuck to the uterosacral ligament or omentum majus,while the endometrium of the right side was implanted onto the right abdominal wall.The second operation was carried out 4 weeks after implantation to evaluate establishment of the models.Samples from the rats were detected with the osteopontin(OPN) antibody and matrix metalloproteinase-9(MMP-9) antibody.Results The achievement ratio of the opening-method model was 81.08%,lower than 83.78% of the transplanting-method model,with no statistical significance(P 0.05).The main gross appearance in the transplanting-method model was clear vesicles in 64.80% of all the rats,followed by dark blue nodules in 10.81%.However,the main appearance was dark blue nodules in the opening-method model in 35.13%,followed by clear vesicles in 24.3%.The adherence rate of abdominopelvic organs was 18.9% in the transplanting-method model,significantly lower than 64.86% in the opening-method model(P 0.01).There was no difference in both intestinal obstruction and infection rates between the two groups(P 0.05).Microscoptic features: typicaland atypical glands and endometrial cells could be found in 72.70% of vesicles and 68.42% of flame signs,with strong staining of OPN and MMP-9 in the ectopic endometrium.Conclusion The two models both have high achievement ratios.The opening-method model is more similar to human endometriosis in gross appearance,with features of reliability,large area,more convenience and with less complications.