CONTRIBUTION OF DIETARY AND LOADING CHANGES TO THE EFFECTS OF SUSPENSION ON MOUSE FEMORA

The present study assessed the contributions of feeding changes and un loading to the overall measured effects of 2-wk hindlimb (Tail) suspen sion on the mouse femora. Feeding changes were addressed by considerin g the effects of matched feeding among suspended and control mice. The effects of hind limb unloading were considered by comparing suspended mice to mice equipped identically (though not suspended) and matched- fed. The feeding and unloading aspects of suspension appear to cause d istinctly differing effects on the stereotypic modeling of the femora. Matched-feeding was accompanied by increased resorption surface in co mparison to suspended mice, while unloading led to reduced bone format ion at the mid-diaphysis of the femora. Reduced mineral content was ob served in the bones of suspended mice when compared to the other mice groups, but without increased resorption surface. Thus, the unloading aspects of the antiorthostatic suspension protocol apparently causes r educed formation and mineralization in the femur. (C) 1994 Wiley-Liss, Inc.