Canonical Wnt signaling is required for Panax notoginseng saponin-mediated attenuation of the RANKL/OPG ratio in bone marrow stromal cells during osteogenic differentiation

Panax notoginseng saponins (PNS) are known to regulate the osteogenic differentiation of bone marrow stromal cells (BMSCs). In the present study, we investigated whether PNS could promote the osteogenic differentiation of BMSCs through modulating the Wnt/β-catenin signaling pathways, which are implicated in BMSCs osteogenesis. We found that PNS enhanced the mRNA expression of OPG, β-catenin, and cyclin D1 while decreased the mRNA expression of RANKL and PPARγ2. The actions of PNS on BMSCs were reversed (or partially) by DKK-1, a classical inhibitor of Wnt/β-catenin signaling. These results suggest that PNS stimulating bone formation by promoting the proliferation and osteogenic differentiation of BMSCs, and could also protect the skeletal system by decreasing bone resorption through reduction of RANKL/OPG expression via Wnt/β-catenin signaling pathways.