BACKGROUND:Previous studies have shown that puerarin can inhibit the differentiation of osteoclasts,and the expression of Notch signaling pathway-related proteins such as Notch1,HES1,and Jagged1 is decreased.However,the specific mechanism of the Notch1 signaling pathway for the inhibition of osteoclast differentiation by puerarin is not clear. OBJECTIVE:To explore the effect of Notch signaling pathway on puerarin inhibiting the differentiation of mouse macrophage Raw264.7 into osteoclasts. METHODS:Raw264.7 cells were divided into seven groups for intervention culture.Blank control group was cultured in high-sugar DMEM medium;the osteoclast induction group was cultured in osteoclast induction medium;the puerarin intervention group was cultured with 50 μmol/L puerarin at the same time of osteoclast induction;Notch1 siRNA control group,Notch1 siRNA group,Notch1 overexpression control group and Notch1 overexpression group were transfected with Notch1 siRNA control sequence,Notch1 siRNA,Notch1 overexpression control plasmid and Notch1 overexpression plasmid,respectively,and then cultured with osteoclast induction medium and puerarin.The number and size of osteoclasts were observed by tartrate-resistant acid phosphatase staining,the skeleton formation of osteoclasts was observed by F-actin staining,and the gene expression level of osteoclast formation markers was detected by RT-PCR. RESULTS AND CONCLUSION:Tartrate-resistant acid phosphatase staining results showed that puerarin intervention could inhibit the generation of osteoclasts,Notch1 silencing could further reduce the number of osteoclasts,while the number of osteoclasts in the osteoclast-induced group increased significantly after Notch1 overexpression.The results of F-actin showed that Raw264.7 cells could form a well-defined F-actin ring after osteoclast induction.Puerarin intervention would inhibit the formation of cytoskeleton,and Notch1 silencing could aggravate the inhibitory effect of cytoskeleton formation,while Notch1 overexpression could alleviate this inhibitory effect of puerarin.RT-PCR results showed that puerarin could inhibit the mRNA expression levels of tartrate-resistant acid phosphatase,Cathepsin K and c-Fos,the expression of the above-mentioned three factors decreased significantly after Notch1 gene silencing,and Notch1 overexpression could upregulate the expression of these factors.These finding indicate that puerarin inhibits the differentiation of Raw264.7 cells into osteoclasts through the Notch signaling pathway.