Porcine endometrial epithelial organoids: Generation, characterization, and the impact of stromal cells.

Endometrial organoids (EOs) are three-dimensional models that emulate the endometrium, serving as an invaluable in vitro tool for investigating the cellular and molecular mechanisms underlying endometrial physiology and pathology during the estrous cycle and pregnancy. While significant progress has been made in the establishment and optimization of EOs for both humans and mice, research on such models in other species remains limited. This study aimed to develop porcine endometrial epithelial organoids (EEOs) to explore the regulatory mechanisms of uterine function and maternal-fetal interactions during porcine pregnancy, which are critical for enhancing reproductive efficiency and improving embryo transfer techniques. Utilizing a defined protocol involving Matrigel and a simplified culture medium, we successfully established EEOs from porcine endometrial epithelial cells, which demonstrated epithelial characteristics, proliferative capacity, glycogen secretion, and hormonal responsiveness. Co-culturing with porcine endometrial stromal cells not only enhanced EEO formation but also mitigated the negative effect of progesterone on glycogen secretion. This cost-effective and efficient method provides a valuable reference for EO generation in other large animal species.