Knee loading and histological observation of the mouse knee. (A) Force profiles for knee loading. A 5 Hz sinusoidal load was applied to the right knee at a magnitude of 0.5 N, 1.0 N, or 3.0 N (peak-to-peak). Sham-loaded controls received a static load of 0.5 N. (B) Force-voltage relationship. To verify peak forces applied to the knee, the loading device was calibrated using a load cell and a linear relationship was defined relating actuator voltage and peak compressive force. (C) Application of knee loading. A custom-made piezoelectric loader was utilized to load the mouse knee.