Immunologic comparisons of strain and induction method in an improved mouse model of intrauterine fibrosis

Intrauterine adhesions are growths of fibrotic tissue within the uterine cavity and can arise from a variety of tissue-damaging stimuli. Immune cells are known to mediate fibrotic responses, but specific mechanisms require further elucidation. Here, we compared intrauterine fibrosis development and immune responses across different mouse strains and induction methods. We aimed to identify a consistent and more clinically relevant mouse model of intrauterine fibrosis, whether immune responses differ in response to different stimuli, and which potential key immune cell populations are responsible for intrauterine fibrosis susceptibility. Intrauterine fibrosis induction methods were compared using surgical curettage or transcervically administered chemical (quinacrine) models. Measurements of tissue morphology and collagen gene expression indicate BALB/c mice are more susceptible than C57BL/6 mice to intrauterine fibrosis. In chemically induced BALB/c uterine tissues, gene expression and flow cytometry data show greater pro-inflammatory macrophage responses, implicating a possible role in fibrogenesis consistent with human intrauterine adhesion data. Findings from this study demonstrate the importance of mouse strain selection in studies of intrauterine adhesions. Furthermore, we show that a new hormone-synchronized, chemically induced mouse model can more uniformly and reliably provoke fibrotic tissue response. This model may allow for greater elucidation of mechanisms involved in intrauterine adhesion development, and exploratory therapeutic studies for treatment intervention.