Figure 4.

Transforming growth factor β (TGFβ) promotes osteoclast differentiation. Tartrate‐resistant acid phosphatase (TRAP) staining of cells from rat bone marrow cultured with α‐modification minimum essential medium alone (a), receptor activator of nuclear factor‐κB ligand (RANKL; 10 ng/mL) (b), RANKL + TGFβ (0.01 ng/mL) (c), and RANKL + TGFβ (0.1 ng/mL) (d) (magnification: ×200). Note the lower number of multinucleated cells induced by medium alone than with RANKL treatment. Additional TGFβ treatment is associated with an extra increment in osteoclasts. (e) Quantitative analysis of TRAP‐positive multinucleated cells. The numbers are averages of quadruplicate values. **P < 0.01; ***P < 0.001.