Establishment of a Rat Model for Intrauterine Adhesions via Dual Injury: Curettage and Infection

Intrauterine adhesions (IUAs), the most common disorders of endometrial injury with incompletely understood etiology, profoundly disrupt female reproductive health. In severe cases, IUAs lead to a postoperative adhesion recurrence rate of 62.5% and a low pregnancy rate of 33.3%. Trauma and infection are recognized as major risk factors. Animal models facilitate a better understanding of the mechanisms underlying this complex disease. Here, we describe a cost-effective rat model mimicking human IUA pathogenesis through dual injury: mechanical endometrial curettage and infection. First, the endometrium was scraped ~30x in each direction (front, back, left, and right) with a curette. Second, a cotton suture impregnated with 6 mg/L lipopolysaccharide was placed in the uterine cavity for 48 h to induce inflammatory damage. Histological changes were evaluated at 7 and 14 days post surgery. Macroscopic examination revealed uterine atrophy and loss of elasticity, while histological analysis showed thinning or absence of the endometrium, decreased glandular number, narrowing or obliteration of the uterine cavity, and increased area of fibrosis. This dual-injury approach efficiently establishes a stable rat IUA model by day 14, recapitulating key clinical and pathological hallmarks of human IUAs.