Qi-Gu capsule alleviates osteoporosis by inhibiting mesenchymal stem cell senescence via the HIF-1α/AMPK axis

Background

Osteoporosis (OP) represents a systemic disease causing reduced bone mass and fragility fractures. Qigu Capsule (QGC), a traditional Chinese medicine, shows potential in alleviating human OP, but its precise mechanisms remain unclear, limiting clinical application.

Methods

The bioactive components of QGC were analyzed using high-performance liquid chromatography (HPLC). An ovariectomy (OVX)-provoked OP rat model was established to evaluate QGC's effects on bone mass, trabecular architecture, and mechanical strength using micro-CT, histological staining, and biomechanical testing. RNA-seq analysis of human OP-derived mesenchymal stem cell (MSC) samples was performed to identify oxidative stress (OxS)- and senescence-associated gene changes. OxS-induced MSC senescence was modeled in vitro using H₂O₂, and QGC's effects on MSC proliferation, migration, and osteogenic differentiation were assessed. Network pharmacology (NP) was deployed to predict the key mechanisms behind the QGC treatment of OP. Further mechanistic studies utilized pharmacological inhibitors and siRNA-mediated gene knockdown to confirm the involvement of critical signaling pathways.

Results

HPLC-MS analysis identified 505 unique bioactive compounds in QGC. In vivo, QGC significantly improved BMD, enhanced trabecular microarchitecture, and restored mechanical properties in OVX rats. ELISA, histological, and immunohistochemical analyses confirmed that QGC primarily enhanced osteoblast activity. RNA-seq analysis of GEO datasets revealed upregulation of senescence and OxS markers (P53, CDKN1A, and INOS) in human OP-derived MSCs. Both in vivo and in vitro QGC alleviated OxS-induced MSC senescence, reduced reactive oxygen species (ROS) levels, suppressed senescence and OxS marker, and promoted MSC proliferation, migration, and osteogenic differentiation. Moreover, NP predicted HIF-1α signaling as critical in QGC's regulation of MSC function during OP. Mechanistic studies demonstrated that QGC activated the HIF-1α/AMPK axis, and inhibition of either HIF-1α or AMPK abolished its therapeutic effects.

Conclusion

QGC mitigates OxS-induced MSC senescence and promotes osteogenesis through the HIF-1α/AMPK axis, highlighting its mechanistic basis in treating OP. These findings show QGC's potential as a therapeutic agent, not only by promoting osteogenesis but also by complementing or serving as an alternative to current OP treatments, offering valuable prospects for enhanced clinical management.