Influence of mechanical forces on bone: Introduction to mechanobiology and mechanical adaptation concept

Mechanical forces (Pressure, shear or elongation) are now considered to be a determining factor in our understanding of many physiopathological mechanisms. These forces influence the cellular metabolism and can lead to tissue remodelling by triggering a cascaded of reactions on cells (mechanotransduction). The first observations of bone adaptation were realized by 2 German surgeons Meyer (1866) and Wolf (1869). They suggested that “the spongiosa showed a well-motivated architecture with is closely connected with the statics and mechanisms of bone”. In 1880, W. Roux introduced the concept of functional adaptation; which can be defined as a quantitative autoregulation controlled by stimuli. In this paper, the influence mechanical forces on bone are summarized and the role of matrix elasticity or scaffold and signaling pathways by which the microenvironment determines the maturation. The in vivo consequences of these adaptive phenomena are described (increased of bone mass seen in athletes of loss of bone tissue during immobilization or bed rest after fracture or also in the astronauts after a long stay in space).