Several investigators have demonstrated a positive correlation between ash density and the compressive strength of bone. However, ash density cannot account solely for the mechanical strength of bone. It has been shown that at high strain rates considerably energy is absorbed by marrow during physiologic loading, thus suggesting an important role of water or fat in strengthening bone. Hydraulic stiffening of bone has been studied with variable result. Stiffness is diminished when fluid is evacuated and can be restored to previous levels when fluid is replaced.
Water constitutes a large part of the fluid content.
In disuse osteoporotic animal models, both an increase and decline of bone water has been demonstrated. However, there are no reports of differences in water content in bones of ovariectomized rats. This study analyzes the compositional changes which occur in bone from ovariectomized rats. Separate anaylsis of cortical and cancellous bone was performed, and water content changes were the focus of this investigation. Proteoglycans are essential to cartilage well being and is the most important matrix component to weight bearing is cartilaginous tissue.