Figure 3. Senescence stimulates RANKL production in murine cells.

(A–E) Bone marrow stromal cells isolated from 6-month-old female mice and cultured with (A and B) 10 μM etoposide or (C–E) 25 μM H₂O₂ for 3.5 days. (A and C) Representative photomicrographs of SA–β-gal staining of stromal cell cultures. Original magnification, ×100. (B and E) Gene expression by quantitative RT-PCR (triplicate cultures). (D) Protein levels by Western blot. (F) Osteocyte-enriched bone shafts isolated from 6-month-old female mice and cultured for 5.5 days after ionizing radiation (IR) exposure to 10 Gy. Protein levels by Western blot (left) and band density quantification (right) from 3 independent mice. Line and error bars represent mean ± SD; P values by 2-tailed unpaired t test.