Celosiae Semen and Celosin I alleviate postmenopausal osteoporosis by inhibiting ferroptosis through the Nrf2/GPX4 pathway

Postmenopausal osteoporosis (PMOP) is characterized by bone loss and high fracture risk, with emerging evidence implicating ferroptosis in its pathogenesis. Celosiae Semen (CS) strengthens bones and contains saponins that may reduce ferroptosis, but the mechanisms are not well understood.

To determine whether total saponins of CS (TSCS) attenuate PMOP through the Nrf2/GPX4 pathway and whether Celosin I (CI) reproduces TSCS's core therapeutic effects.

Network pharmacology identified CS-related targets and pathways in osteoporosis. TSCS components were analyzed by HPLC. In vivo, ovariectomized (OVX) mice received TSCS or CI for 12 weeks, and bone microarchitecture was assessed by micro-CT. In vitro, tert‑butyl hydroperoxide (t-BHP) induced ferroptosis in bone marrow mesenchymal stem cells (BMSCs), followed by TSCS or CI treatment. Ferroptosis markers, mitochondrial function, and osteogenesis were evaluated via biochemical assays and Western blot. Molecular docking assessed compound-target interactions. Nrf2 knockout models were used to validate pathway dependence.

TSCS significantly alleviated OVX-induced bone loss, improving bone mineral density and trabecular structure. It reduced lipid peroxidation, restored glutathione levels, and upregulated Nrf2 and GPX4. CI reproduced TSCS's anti-ferroptotic and pro-osteogenic effects in vivo and in vitro and showed strong binding affinity for Nrf2 and GPX4. Importantly, the protective effects of both TSCS and CI were markedly diminished in Nrf2-deficient models, confirming dependence on the Nrf2/GPX4 axis.

TSCS mitigates PMOP progression by suppressing ferroptosis via Nrf2/GPX4 activation. CI replicates TSCS's therapeutic benefits, identifying both as promising candidates for targeting ferroptosis in osteoporosis.