Tanshinone IIA Regulates Osteoblast Differentiation and Promotes Fracture Healing via Mammalian Target of Rapamycin Complex 1 Signaling Pathway

This study assessed the effect and potential molecular mechanism of tanshinone IIA on fracture healing. Mice model with fracture were established. Digital radiographic photographic system was used to detect callus formation after treatment with tanshinone II A (Tan IIA) and alkaline phosphatase (ALP) staining analyzed ALP activity. Osteoblast proliferation was also measured. Western blot and Quantitative real-time PCR (qRT-PCR) measured osteogenic markers expression. Compared with control group, Tan IIA treatment could increase callus formation, stimulate osteoblast proliferation, osteogenic proteins and genes expression, and activate mTORC1 signaling pathway. However, Tan IIA's effects were significantly inhibited after rapamycin treatment. Tan IIA regulates osteoblast differentiation by mTORC1 signaling and promotes intramembranous ossification in the process of callus formation, which accelerates bone healing.