Figure 1.

Erythropoietin (EPO) and ephrinB2 induce an osteoblastic phenotype. ST2 cells were cultured in osteogenic medium with EPO and/or ephrinB2-Fc. RNA was extracted on day 4 or 6, and expression of EphB4 (A), Runx2, Sp7, and Col1 (B) in ST2 cells was quantified by qRT-PCR. Alkaline phosphatase (ALP) activity was analyzed on days 7 and 14 (C). Protein levels of EphB4 were analyzed by Western Blot and quantified by Image J 1.48p (D). Alizarin red staining was performed on days 14 and 21; the stained samples were eluted with 10% cetylpyridinium chloride; and the absorbance was measured (E). Data shown are mean ± SD. These assays were repeated 3 times. ^*P < 0.05; ^**P < 0.01.