Sambucus Williamsii Hance Promotes MC3T3‐E1 Cells Proliferation and Differentiation via BMP‐2/Smad/p38/JNK/Runx2 Signaling Pathway

The 50% ethanol elution fractions of root-bark of Sambucus Williamsii Hance (rbSWH) evaluated the effect of proliferation and differentiation on preosteoblast MC3T3-E1 cell, and the mechanism of actions. We found that rbSWH(30, 60, and 90 µg/mL) can enhance cell proliferation by MTT assay and promote alkaline phosphatase (ALP) and bone Gla protein (BGP) activities, type I collagen (Col-I) synthesis, and mineralization nodule formation in primary cultured osteoblasts. The results showed that rbSWH can increase mRNA levels of BMP-2 and Runx2 using real-time reverse transcription-quantitative polymerase chain reaction, whereas the BMP-2 antagonist Noggin attenuated the increase of ALP activity induced by rbSWH, indicating that BMP-2 expression was required for the action of rbSWH in osteoblastic. We also found that rbSWH can enhance the expressions of BMP-2, BMPRIB, BMPRII, phosphorylation of Smad, JNK and p38, and Runx2 proteins by western blotting. In addition, pretreatment of cells with p38 inhibitor (SB203580) or JNK inhibitor (SP600125) can antagonize the elevation of BMP-2 expression, ALP activity, and cell viability induced by rbSWH. Taken together, our results provided an evidence that rbSWH can promote MC3T3-E1 cell proliferation and differentiation via BMP-2/Smad/p38/JNK/Runx2 signaling pathway.