Isorhamnetin-preconditioned MSC-derived exosomes restore ovarian function by inhibiting ferroptosis in chemotherapy-induced POF.

BACKGROUND: Chemotherapy-induced premature ovarian failure (POF) is a major cause of infertility, with limited treatment options. Mesenchymal stem cell-derived exosomes (MSC-Exos) have therapeutic potential. This study investigated whether preconditioning MSCs with the antioxidant flavonoid isorhamnetin (ISO) enhances the efficacy of their exosomes (ISO-MSC-Exos) against POF. METHODS: A cyclophosphamide-induced POF rat model was established, and the role of the ferroptosis inhibitor ferrostatin-1 was evaluated. MSC-Exos and ISO-MSC-Exos were isolated by ultracentrifugation and administered via tail vein injection. Ovarian recovery was assessed by monitoring the oestrous cycle, serum hormone levels, and histological findings. Lipid peroxidation and iron metabolism were evaluated by quantifying malondialdehyde, glutathione, iron deposition, and mitochondrial ultrastructure. Immunohistochemistry was used to assess the expression levels of GPX4, ACSL4, and FTH1. Proteomic analyses were performed to explore the underlying mechanisms. RESULTS: Ferroptosis plays a pivotal role in the cyclophosphamide-induced POF rat model. Both exosome therapies improved ovarian function and suppressed ferroptosis, with ISO-MSC-Exos showing superior efficacy. ISO-MSC-Exos significantly restored hormone levels, ameliorated oestrous cycle disorders, reduced follicular atresia, and enhanced fertility. Furthermore, ISO-MSC-Exos more effectively elevated glutathione levels, reduced malondialdehyde and Fe CONCLUSIONS: ISO-MSC-Exos showed superior efficacy compared with MSC-Exos in restoring ovarian function and inhibiting ferroptosis, suggesting that ISO pretreatment enhances the therapeutic effect of MSC-Exos in the POF model. Proteomic data provided supportive mechanistic insights into this enhanced efficacy, with the key pathways identified requiring subsequent functional validation.