Construction and evaluation of intrauterine adhesion model in rats by different methods of mechanical injury

Purpose The study aimed to establish a stable and effective animal model for the experimental study of intrauterine adhesion (IUA) by evaluating various mechanical injury methods. Methods A total of 140 female rats were divided into four groups according to the extent and area of endometrial injury: group A (excision area: 2.0 × 0.5 cm 2 ), group B (excision area: 2.0 × 0.25 cm 2 ), group C (endometrial curettage) and group D (sham operation). On the 3rd, 7th, 15th and 30th day after the operation, the tissue samples of each group were collected, and the uterine cavity stenosis and histological changes were recorded by HE and Masson staining. Immunohistochemistry of CD31 was applied to visualize microvessel density (MVD). The pregnancy rate and the number of gestational sacs were used to evaluate the reproductive outcome. Results The results showed that endometrium injured by small-area endometrial excision or simple curettage could be repaired. The ratio of fibrosis in groups A and B was higher than that in groups C and group D 30 days after modeling ( P < 0.001). The number of endometrial glands and MVD in group A was significantly lower than those in groups B, C and D ( P < 0.05). The pregnancy rate in group A was 20%, which was lower than that in groups B (33.3%), C (89%) and D (100%) ( P < 0.05). Conclusion Full-thickness endometrial excision has a high rate of success in constructing stable and effective IUA models in rats.