Biomechanical performance of diaphyseal shafts and bone tissue of femurs from protein-restricted rats

Abstract

The aim of this study was to define the biomechanical repercussion of a severe protein restriction on the shaft of long bones and on cortical bone tissue. Femurs from 9 rats fed a protein-free diet from the 30th to the 50th day of age showed a great reduction of bending strength and stiffness with respect to 9 controls. These alterations correlated with severe impairment in the amount and/or the architectural arrangement of bone material (volume, wall/lumen ratio, sectional inertia) and also with reduction of Ca content and modulus of elasticity of bone tissue. No changes were observed, however, in bone elastic stress. The impairment in stiffness derived from reductions in both bone mass and modulus of elasticity led to an increment in energy absorption by bone and bone tissue which in turn induced a high incidence of comminuted fractures. The data provide a biomechanical basis for the interpretation of clinical features of nutritional osteopenia in long bones.