Integrative Proteomics Reveals That Ejiao Alleviates Premature Ovarian Insufficiency and Restores Bone Metabolism in Mice

Background: Premature ovarian insufficiency (POI) is an intractable reproductive endocrine disease characterized by accelerated ovarian aging, accelerated follicle depletion and hormonal disorders, leading to secondary bone metabolic dysfunction and impaired long-term female health. Conventional hormone replacement therapy is the guideline-recommended first-line therapy for young women with POI, yet its long-term safety must be individualized; natural nutritional interventions are best viewed as complementary strategies. Donkey-hide gelatin (Ejiao), a natural food rich in bioactive collagen and amino acids, is commonly used for female reproductive care. Nevertheless, its systematic efficacy and molecular mechanisms against POI and related bone complications remain poorly defined. Methods: This study established a tripterygium glycosides (TG)-induced POI mouse model. Mice received low-dose (1.5 g/kg) and high-dose (3.0 g/kg) Ejiao treatment for 30 consecutive days. Reproductive organ morphology, estrous cycle, serum hormone levels, ovarian histopathology, bone microarchitecture and ovarian proteomic profiles were assessed. Results: Ejiao remarkably restored ovarian index and tended to improve uterine index (non-significant), corrected estrous cycle disturbance, and partially corrected the endocrine profile (E2, AMH, GnRH). It upregulated the ovarian reserve markers E2 and AMH and downregulated GnRH. Histological examination verified improved follicular development and reduced atresia. Furthermore, Ejiao alleviated POI-induced bone loss, optimized trabecular microstructure and rescued abnormal RANKL/OPG ratio to stabilize bone metabolism. Proteomic analysis revealed 313 differentially expressed proteins (DEPs) between Ejiao-treated and model groups, with enrichment in calcium signaling, cAMP, cGMP-PKG, and TGF-β/Smad pathways. Conclusions: As a natural bioactive food, Ejiao exerts dual protective effects against POI and concurrent bone metabolic dysfunction associated with modulation of multiple core signaling pathways and functional proteins (suggesting involvement of these pathways in its effects).