Proliferative activity of osteoclast progenitor cells.

(A) c-Fms⁺RANK⁻ cells were cultured in the presence of M-CSF alone or M-CSF and sRANKL together with 0.5 mg/mL GRGDS or GRGES peptide for 48 hours. Then the DNA content (PI, x axis) and the expression of PCNA (y axis) were analyzed. (B) The frequency of PCNA⁺ cells was quantified by comparison with an isotype-matched control. Aggregated cells were excluded by PI gate. The percentage of PCNA⁺ cells was reduced in the presence of sRANKL and by addition of the GRGDS peptide.