Fig. 2. Osteoclastogenesis in the presence or absence of tocilizumab and/or 1,25(OH)₂D₃. Peripheral blood mononuclear cells obtained from healthy donors (n = 3) were differentiated into osteoclasts with RANKL and M-CSF treatment in presence or absence of various concentrations of tocilizumab and/or 1,25(OH)₂D₃. (A) Representative H&E stain, (B) number of TRAP-positive giant cells, relative mRNA expressions of (C) RANK, (D) MMP9, and (E) cathepsin K.

RANKL = receptor activator of nuclear factor kappa-B ligand, M-CSF = macrophage colony-stimulating factor, H&E = hematoxylin and eosin, TRAP = tartrate-resistant acid phosphatase, RANK = receptor activator of nuclear factor kappa-B, MMP9 = matrix metalloproteinase 9, TCZ = tocilizumab, V.D. = vitamin D.

^*P < 0.05; ^**P < 0.01.