A Hydrogel-Based In Vitro Coculture Model for Studying Aging-Associated Granulosa Cell–Endothelial Cell Interaction

Background: A suitable biomaterial scaffold is essential for building in vitro ovarian models. This study developed a GelMA/HAMA (GH) hydrogel to support granulosa cell culture and to construct a simplified coculture system for granulosa cell–endothelial cell interaction. Methods: GH hydrogel was characterized by rheology, tensile testing, scanning electron microscopy, swelling, degradation, and extract-based cytocompatibility. KGN granulosa cells were encapsulated in GH hydrogel, and an aging-like model was induced with H₂O₂. A Transwell system and conditioned-medium experiments were used to evaluate endothelial cell responses. Results: GH hydrogel showed light-triggered gelation, predominantly elastic behavior, higher tensile performance than GelMA, lower swelling, and slower degradation, with acceptable cytocompatibility at the tested range. In KGN-laden hydrogels, H₂O₂ treatment increased ROS and p16 expression while decreasing E2 secretion and StAR expression. Conditioned medium from aging granulosa cells increased ROS and VCAM-1 and reduced HUVEC viability. Conclusion: GH hydrogel provides a controllable matrix for granulosa cell culture and a useful in vitro platform for studying aging-related granulosa cell–endothelial cell crosstalk.