Yougui Pills Alleviate Osteoporosis by Inhibiting Mesenchymal Stem Cell ROS Accumulation via the Nrf2/HO-1 Pathway.

Osteoporosis (OP) is a prevalent skeletal disorder characterized by progressive bone mass loss and deteriorated microarchitecture, in which oxidative stress-induced mesenchymal stem cell (MSC) dysfunction serves as a core pathogenic mechanism. Yougui Pills (YGPs), a classical traditional Chinese medicine formula, are widely applied in clinical OP management, yet the cellular and molecular mechanisms underlying their anti-osteoporotic effects remain incompletely defined. This study aimed to elucidate the bone-protective role of YGPs in OP and explore the underlying mechanism, focusing on oxidative stress modulation in MSCs and the Nrf2/HO-1 signalling pathway. The bioactive components of YGPs and YGP-containing serum were characterized via UPLC. In vivo, an ovariectomy (OVX) mouse model was established to evaluate YGPs' effects on bone mass, trabecular microstructure and osteogenesis using micro-CT, histological and immunohistochemical assays; public GEO datasets were re-analysed to profile transcriptomic alterations and oxidative stress signatures in OP-derived MSCs. In vitro, H2O2 was used to induce ROS accumulation and oxidative injury in MSCs, with assessments of cell proliferation, apoptosis, ROS levels, migration and osteogenic differentiation. Network pharmacology and siRNA-mediated gene silencing were conducted for target prediction and mechanistic validation. In vivo results showed that YGP treatment significantly ameliorated OVX-induced osteopenia, increased bone mineral density, improved trabecular microstructure, and upregulated osteogenic markers (ALP, OCN, Runx2, COL1A1). Transcriptomic re-analysis revealed upregulated oxidative stress markers in OP MSCs, consistent with In vitro findings that YGPs attenuated H2O2-triggered ROS overproduction, suppressed apoptosis and ectopic lipid deposition, and enhanced MSC proliferation, migration and osteogenic differentiation. Mechanistically, YGPs activated the Nrf2/HO-1 signalling axis, while Nrf2 knockdown abrogated YGPs' cytoprotective and pro-osteogenic effects. In conclusion, YGPs mitigate oxidative stress-induced MSC dysfunction and promote osteogenesis via the Nrf2/HO-1 pathway, supporting YGPs as a promising therapeutic candidate for OP.