DNA changes in mechanically deformed osteoblasts: a new hypothesis

The available evidence strongly implicates the osteoblast as the key regulator of bone remodelling activity. Since orthodontic tooth movement is a potent inducer of such activity it is relevant to study the effect of mechanical forces on this cell population. The development of a model for mechanically deforming monolayer cultures of cells is described. The effect of mechanical forces on osteoblast-like cells was examined by a number of parameters. Changes in DNA synthesis seen in short-term experiments were at variance with previous published data. The data derived from longer term experiments was in close agreement with in vivo models; intermittent forces producing an increase in DNA synthesis when compared to static or continuous forces. These changes are discussed in relation to current perspectives of second messenger activation by mechanical strain. Prostaglandins did not appear to mediate these events. There was also no evidence that synthesis of the cytokine, interleukin-1 (IL-1), or the metalloproteinase, collagenase was altered by mechanical forces.