Figure 2: Melatonin treatment improved periprosthetic bone mass, promoted osteogenesis, and increased implant fixation strength. (a) H&E staining. Scale bar, 500 μm. (b) Toluidine blue staining. Scale bar, 100 μm. (c) High-magnification fluorochrome images. Scale bar, 100 μm. (d) BV/TV (%, fold of control) from H&E staining, per group. (e) Tb.N (1/mm, fold of control) from toluidine blue staining, per group. (f) Mineral apposition rate (MAR) (μm/d, fold of control) from high-magnification fluorochrome images, per group. (g–l) Immunostaining of bone formation markers (ALP, OCN, and osterix). Scale bar, 50 μm, per group. (m) Mechanical pull-out test (maximal fixation strength, N), per group. and .