FIGURE 8.
Baicalin induces the expression of Runx2 in cultured osteoblasts. A, baicalin at different concentrations was applied onto cultured osteoblasts for 2 days, with or without the pretreatment of DKK-1 (0.2 mg/ml) for 1 h. Total RNAs were extracted from cultures to perform quantitative PCR for Runx2 mRNA. B, cultured osteoblasts were treated with baicalin at different doses for 48 h, as indicated. The expressions of Runx2 (at ∼57 kDa) were revealed by specific antibodies in a Western blot analysis. Wnt3a (200 ng/ml) served as the positive control. C, two reporter constructs were used here in the transfected osteoblasts. pWREmRUNX2-Luc contained a luciferase (Luc) enzyme tagged downstream of the TCF-binding element in responding to Wnt/β-catenin signaling, and pΔWREmRUNX2-Luc had a mutation on the TCF-binding site (upper panel). In the transfected osteoblasts, baicalin (50 μm) was applied for 2 days. The cell lysates were collected for luciferase assays. Values are expressed as the fold of increase to basal reading (control culture treated with 0.02% DMSO) and are means ± S.E., where n = 5, each with triplicate samples. *, p < 0.05.