Figure 2.

Mechanical stimulation promotes osteogenic differentiation of bone-marrow–derived cells. A) Experimental timeline. B) Sixteen-week-old nonloaded control animal. Bone marrow–derived cells were detected only within the endocortical region (arrows). C) Control animal after mechanical loading. Bone marrow–derived cells were embedded within the endocortical and periosteal bone (arrows). D) Experimental animal after mechanical loading. Bone marrow–derived cells were also embedded in endocortical bone (X, arrow), but fewer were detected in the periosteal region (Y, arrow) than in the control animals illustrated in (C).