Abstract
The purpose of this study was to evaluate the effects of mechanical loading on cultured osteogenic cells from different stages of bone wound healing. A bone cavity was created in a rat femur, and cells were obtained from the cavity during various phases of wound healing: the blood clot (BC) stage, the development of granulation tissue (GT), and callus formation (CF). After 7 days of primary culture, mechanical loading was applied once a day. Cells without mechanical loading were used as controls. Cell proliferation, alkaline phosphatase (ALP) activity and expression of mRNAs of both bone sialoprotein (BSP) and osteopontin (OPN) were evaluated. Cell proliferation of BC cells was significantly inhibited by mechanical loading. However, GT cells were significantly up-regulated by ALP activity at day 5, as were the expressions of BSP and OPN mRNAs at day 7 by mechanical loading. These results suggest that cells in bone granulation tissues have the ability to transduce mechanical stress to osteogenic differentiation.
