Effects of rehydration state on the flexural properties of whole mouse long bones

The effects of bone water content during dehydration and rehydration on the flexural properties of whole mouse femora were evaluated using three-point bending. The elastic and plastic flexural properties of the bones were determined on a dry mass normalized basis over dehydration times ranging from 0.25 to 48.0 hr; and (following complete dehydration) rehydration times ranging from 0.08 to 12.0 hr. Bones stored in physiological saline for times < 1 hr served as the control group. As expected, dehydration produced increased stiffness and strength along with decreased ductility. Upon rehydration, a statistically significant linear dependence of mechanical properties on recovered free water was obtained for all parameters except the maximum load. Elastic mechanical properties comparable to the controls were regained at differing rates and levels of recovered water content; however, after 3 hr of rehydration there were no statistically significant differences with respect to the control values. The results of this study indicate that the original flexural properties of whole mouse femora are preserved by air dehydration and can be recovered using appropriate saline rehydration intervals.