Vonoprazan attenuates cyclophosphamide-induced ovarian injury in rats via modulation of TLR4/NF-κB and AMPK/SIRT1/Nrf2/HO-1 signaling.

Cyclophosphamide (CPA) is a widely used alkylating agent that causes premature ovarian insufficiency (POI), a major reproductive risk for young female cancer survivors. This study examined whether vonoprazan (VON), a potassium-competitive acid blocker with reported cytoprotective activity in non-gastric tissues, protects against CPA-induced ovarian injury in female Wistar albino rats, and characterized the signaling changes that accompany this protection. Rats (n = 10 per group) received saline, VON (20 mg/kg/day, p.o.), CPA (200 mg/kg i.p. on day 1 followed by 8 mg/kg/day for 14 days), or CPA with concurrent VON. CPA reduced body and ovarian weights, disrupted estrous cyclicity, lowered serum estradiol and AMH while raising FSH, increased ovarian lipid peroxidation and pro-inflammatory cytokines, depleted antioxidant enzymes, elevated cleaved caspase-3, upregulated TLR4 and NF-κB p65, and reduced p-AMPK, SIRT1, Nrf2 and HO-1. Histological examination confirmed widespread follicular degeneration and loss of follicles across all developmental classes. Concurrent VON significantly attenuated each of these changes and preserved ovarian architecture and follicular reserve. These findings show that VON, given alongside CPA, protects the rat ovary against alkylating-agent injury, and that this protection is associated with suppression of TLR4/NF-κB signaling and restoration of the p-AMPK/SIRT1/Nrf2/HO-1 axis. Because pathway involvement was inferred from changes in protein abundance rather than tested by pharmacological or genetic interruption, these associations require causal confirmation, and the relevance of VON to clinical fertility preservation remains to be established.