Effects of Tanshinone IIA on osteogenic differentiation of mouse bone marrow mesenchymal stem cells

Tanshinone IIA (TSA) is a lipophilic diterpene purified from the Chinese herb Danshen, which exhibits potent antioxidant and anti-inflammatory properties. Effect of TSA remains largely uninvestigated on the osteogenic differentiation of bone marrow mesenchymal stem cells (BM-MSCs), which are widely used in cell-based therapy of bone diseases. In the present study, both ALP activity at day 7 and calcium content at day 24 were upregulated during the osteogenesis of mouse BM-MSCs treated with TSA (1 and 5 μM), demonstrating that it promoted the osteogenesis at both early and late stages. We found that TSA promoted osteogenesis and inhibited osteoclastogenesis, evident by RT-PCR analysis of osteogenic marker gene expressions. However, osteogenesis was inhibited by TSA at 20 μM. We further revealed that TSA (1 and 5 μM) upregulated BMP and Wnt signaling. Co-treatment with Wnt inhibitor DKK-1 or BMP inhibitor noggin significantly decreased the TSA-promoted osteogenesis, indicating that upregulation of BMP and Wnt signaling plays a significant role and contributes to the TSA-promoted osteogenesis. Of clinical interest, our study suggests TSA as a promising therapeutic strategy during implantation of BM-MSCs for a more effective treatment of bone diseases.