Figure 6
Measurement of bone-resorbing activity in CaP-coated plates. (a) RAW264.7 cells were cultured on CaP-coated 96-well plates in RANKL-containing medium for 4, 5, 7, and 9 d. Cells were also cultured in RANKL-free medium for 9 d, as a negative control. Representative images of the pit-formation are shown. Scale bar: 2 mm. (b) Opto-RANKc cells were cultured on collagen-coated plates for 4 d and passaged to CaP-coated plates. Cells were cultured for a total of 9, 11, and 13 d, with blue light exposure every 2 min. Cells were also cultured in the dark for a total of 13 d. Representative images of the pit-formation are shown. Scale bar: 2 mm. (c) Measurement of the pit areas in (a). (d) Measurement of the pit area in (b). The data in (c) and (d) represent the percentage of the pit area to that of the entire area in the well, represented as mean ± SD [n = 6 from six independent experiments for (c) and n = 9 from three independent experiments for (d)]. Data were analyzed using one-way analysis of variance followed by Tukey’s multiple comparisons test. ***, p < 0.001. RANKL, receptor activator of nuclear factor-kB ligand; CaP, calcium phosphate.
