The inhibitory effect of salidroside on RANKL-induced osteoclast formation via NFκB suppression

Bone fractures are a prevalent clinical issue, and recent studies highlighted the promising potential of natural bone healing agents in enhancing fracture repair and regeneration. The regulatory interaction mechanism between osteoblasts and osteoclasts is crucial for bone cell biology and bone disease. In Mongolian medicine, people have used the Rhodiola rosea (R. rosea) extract to accelerate bone healing in bone fractures. Salidroside is a bioactive compound of R. rosea. Salidroside is known to regulate bone metabolism and inhibit the activation of osteoclast cells, but how it affects the differentiation of osteoclasts is unknown. We examined the effect of R. rosea extract and its bioactive compound salidroside on the RANKL-induced osteoclast formation in RAW 264.7 cells. The present study observed that salidroside directly inhibits RANKL-induced TRAP-positive osteoclast formation. Immunoblotting analysis revealed that salidroside inhibited the expression of c-Fos and NFATc1, osteoclastogenic key transcription factors, by suppressing late activation of p65 NFκB. Further, the ethanol extracts of R. rosea significantly reduced the RANKL-induced osteoclasts in a dose-dependent manner. In conclusion, salidroside inhibits RANKL-induced osteoclast formation via suppressing the NFκB/c-Fos/NFATc1 signalling pathway. R. rosea, a primary source of salidroside, is helpful for bone healing via its inhibitory effect on osteoclast formation.