Diaphyseal bone formation in murine tibiae in response to knee loading

cal stimulation is critical for bone architecture and bone mass. The aim of this study was to examine the effects of mechanical loads applied to the knee. The specific question was whether loads applied to the tibial epiphysis would enhance bone formation in the tibial diaphysis. In C57/BL/6 mice, loads of 0.5 N were applied for 3 min per day for 3 days at 5, 10, or 15 Hz. Bone samples were harvested 13 days after the last loading. The strains were measured 13 2 strains at 5 Hz in the diaphysis. The histomorphometric data in the diaphysis clearly showed enhanced bone formation. First, compared with non-loaded control the cross-sectional cortical area was increased by 11% at 5 Hz and 8 % at 10 Hz (both P 0.05). Second, the cortical thickness was elevated by 12 % at 5 Hz (P 0.01) and 8 % at 10 Hz (P 0.05). Third, mineralizing surface (MS/BS), mineral apposition rate (MAR), and bone formation rate (BFR/BS) were increased at 5 Hz (P 0.01 for MS/BS; P 0.001 for MAR and BFR/BS) and a