Achyranthes bidentata saponins promote osteogenic differentiation of bone marrow stromal cells through the ERK MAPK signaling pathway.

Achyranthes bidentata, is a herbal plant commonly used in the treatment of osteoporosis and bone nonunion in the Traditional Chinese Medicine. Saponins are the major compounds extracted from Achyranthes bidentata that have been shown to exert various pharmacological activities such as anti-inflammatory, antipyretic, antirheumatic, diuretic, and anti-osteoporosis. The Achyranthes bidentata saponins (ABS) were found to induce proliferation and differentiation in bone marrow stromal cells (BMSCs) as determined by the cell proliferation and alkaline phosphatase assays. Also, following the osteogenic induction, cells treated with ABS showed increased mRNA levels of rat bone morphogenetic protein-2, runt-related transcription factor 2, and osterix. Furthermore, ABS stimulated the activation of ERK as evidenced by increased phosphorylation of these proteins, which was blocked by an inhibitor of ERK (PD98059). Taken together, these results suggest that ABS stimulated osteogenic differentiation of BMSCs via activation of the ERK signaling pathway.