Effects of medicinal herb salvia miltiorrhiza on osteoblastic cells in vitro

Sufficient osteoinduction is essential for the success and effectiveness of bone grafting. It was previously found that Salvia Miltiorrhiza (SM), a commonly used Chinese herb increased osteogenesis in vivo. The aim of this study is to investigate the effects of SM on bone cells in vitro, in an attempt to get a better understanding on how SM can promote bone remodeling. MC3T3-E1, an osteoblastic cell line, was cultured with SM for different time intervals (24, 48, and 72 h), whereas the control group consisted of cells cultured without any intervention. The mRNA expression of alkaline phosphatase (ALP), osteocalcin (OCN), osteoprotegerin (OPG), and the receptor activator of nuclear factor kappa B ligand (RANKL) were examined by real-time polymerase chain reaction (qPCR). The expression of ALP showed an early increase at 24 h by 50% (p < 0.001) and at 48 h by 13% (p < 0.001). OCN was decreased by 22% at 24 h (p < 0.001) but increased by 50% and 88% at 48 and 72 h, respectively (p < 0.001). RANKL showed an early increase at the first two time points of 24 and 48 h by 45% (p < 0.001) and 36% (p < 0.01), respectively, while OPG was up-regulated at the latter two time points by 10% at 48 h (p < 0.01) and 68% at 72 h (p < 0.001). Thus, OPG/RANKL was down-regulated first, and then up-regulated. SM enhances bone remodeling by regulating the gene expression of ALP, OCN, OPG, and RANKL. It is a potential medicinal herb to be utilized in the application that requires stimulation in bone cell activities.