Figure 5
mRNA expression of genes related to osteoclast differentiation and function in Opto-RANKc cells induced using blue light. (a–b) Opto-RANKc cells were cultured with and without blue light exposure every 2 min. As a positive and negative control for differentiation, RAW264.7 cells (WT) were cultured in the presence and absence of RANKL, respectively. mRNA expression of Acp5 (encoding TRAP), Nfatc1, and Mmp9 was analyzed using quantitative PCR. Relative expression levels are normalized to the corresponding expression in RAW264.7 cells without RANKL and blue light. Relative gene expression in cells cultured for (a) 5 d and (b) 7 d. (c) RAW264.7 cells were exposed to blue light every 2 min for 7 d. The relative expression of Acp5, Nfatc1, and Mmp9 is shown. All data represent mean ± SD from six (a) and four (b-c) independent experiments for WT without RANKL and blue light and three independent experiments for others. Data in (a) and (b) were analyzed using one-way analysis of variance followed by Tukey’s multiple comparisons test. Data in (c) were analyzed using two-tailed unpaired t-test for comparisons between two samples. *, p < 0.05; **, p < 0.01; ***, p < 0.001. RANK, receptor activator of nuclear factor-kB; RANKL, receptor activator of nuclear factor-kB ligand; WT, wild-type; TRAP, tartrate-resistant acid phosphatase; Acp5, acid phosphatase 5, tartrate resistant; Nfatc1, nuclear factor of activated T cells, cytoplasmic 1; Mmp9, matrix metallopeptidase 9.
