Serum Proteomic and Metabolomic Profiling Uncovers Molecular Mechanisms in Patients Undergoing In-Vitro Fertilization with the GnRH Antagonist Protocol

Objectives Infertility is a global health challenge commonly treated with assisted reproductive technology (ART), particularly gonadotropin-releasing hormone (GnRH) antagonist protocols. However, the molecular mechanisms remain unclear. This study aimed to analyze serum proteomic and metabolomic profiles during the menstrual cycle (M) and ovum pick up day (OPU) in patients under this protocol. Design: Ten patients undergoing the GnRH antagonist protocol were enrolled. Serum samples collected during the M and OPU phases were used for proteomics and non-targeted metabolomics analyses. Functional enrichment, protein-protein interaction (PPI), and correlation analyses were performed. Results Clinical indicators confirmed the efficacy of the GnRH antagonist protocol, as evidenced by an anti-Müllerian hormone level of 3.70 ng/ml, significantly elevated sex hormone levels at OPU, and 15.3 oocytes and 5.3 embryos retrieved. Proteomics identified 83 differentially expressed proteins enriched in cell cycle, AMPK, oocyte meiosis, and PI3K-Akt pathways, with core regulatory proteins including RPL23, TCP1, and PRDX1. Metabolomics revealed 66 differential metabolites involved in steroid hormone biosynthesis, glutathione, and purine metabolism pathways. Integrated analysis obtained 192 significantly correlated protein-metabolite pairs, emphasizing the glutathione, purine metabolism, and nucleotide sugar biosynthesis pathways. Key relationships such as NUDT16-inosine and GSR-glutathione were also identified. Conclusion This study firstly revealed the dynamic changes in the serum proteome and metabolome between the M and OPU phases under the GnRH antagonist protocol. The study highlighted the role in regulating hormone synthesis, oxidative balance, and energy supply to support follicular development. These findings provide new insights and potential biomarkers for improving IVF outcomes.