Abstract: Objective　To investigate the inhibitory effect of salidroside (SAL) on osteoclast differentiation and polarization. Methods　RAW264.7 cells were cultured in vitro and induced into osteoclasts by adding solvable receptor activator of nuclear factor kappa B ligand (sRANKL) for 5 days. The control group (culture medium without SAL) and the experimental group (culture medium with SAL in dosage of 15, 30, 60 mg/L respectively) were set. The results of inducing differentiation were compared by TRAP staining. F-Actin ring formation and osteoclast calcification were compared by phalloidin staining and alizarin red staining. Real time fluorescent quantitative reverse transcription polymerase chain reaction (qPCR) was used to detect expression levels of MMP-9, c-Src, CK and Integrin β3. The expression levels of MMP-9 and c-Src proteins were detected by Western blot assay. Results　Compared with the control group, the number of TRAP positive cells, and F-Actin ring formation were significantly reduced in each experimental group. The calcification of osteoclasts and the alizarin red staining of osteoclasts were significantly deepened, indicating the the increased calcification (P＜0.05). Compared with the control group, the expression levels of MMP-9, CK and c-Src mRNA decreased in the 30 and 60 mg/L SAL groups, and the expression levels of MMP-9 and c-Src protein decreased significantly in each group. Conclusion　Salidroside can inhibit the differentiation, polarization and bone resorption of osteoclasts, and its mechanism may be related to the down-regulation of MMP-9 and c-Src expression.

Key words: rhodiola, osteoclasts, cell differentiation, salidroside, cell polarization, bone resorption