具有腔上皮样结构的小鼠子宫内膜类器官的体外构建

Embryo implantation requires coordinated interactions between the embryo and the maternal endometrium. Endometrial organoids (EOs) have emerged as promising <i>in</i> <i>vitro</i> models for studying this process. At present, however, mouse-derived EOs (mEOs) are predominantly composed of a single epithelial cell type and lack a functional luminal epithelium (LE), cellular diversity, and hormonally responsive architecture, limiting their capacity to recapitulate the dynamic receptive phase of the endometrium. In this study, a robust three-dimensional mouse endometrial assembloid model was established by co-culturing endometrial gland-like organoids (GLOs) with primary endometrial stromal cells (ESCs) under air-liquid interface (ALI) conditions. Optimization of the GLO culture was achieved by fine-tuning the concentrations of Wnt3a and R-Spondin1, while stromal viability and functionality were enhanced by supplementation with hydrocortisone, L-ascorbic acid, and ITS-X. Comparative analysis demonstrated that ALI conditions significantly enhanced epithelial proliferation, gland morphogenesis, and metabolic activity across both epithelial and stromal compartments. Notably, the resulting ALI-grown mouse endometrial assembloids (ALI-mEnAOs) developed a well-defined LE layer and recapitulated molecular and cellular features characteristic of both pre-receptive and receptive endometrial states <i>in</i> <i>vivo</i>. Compared to existing mEOs, analyses confirmed that ALI-mEnAOs closely mimic <i>in vivo</i> endometrial architecture, lineage composition, phase-specific gene expression signatures, and dynamic hormonal response. This model offers a physiologically relevant platform for mechanistic investigation of endometrial function and embryo implantation dynamics.