Platelet releasate increases the proliferation and migration of bone marrow‐derived cells cultured under osteogenic conditions

Concentrated platelets and their products are currently being used as a clinical tool to accelerate endosseous wound healing. However, there is little understanding regarding the actions of platelets and platelet‐released products on osteogenic cells. We show, herein, that releasate from thrombin‐activated platelets increases the migration and proliferation of osteogenic cultures of bone marrow cells. Using a scratch wound assay, we demonstrated that platelet releasate (PR) stimulated up to a 2.4±0.5‐fold increase in wound closure in serum‐free medium, relative to a control containing thrombin. In the presence of serum, the addition of PR resulted in a 1.45±0.13‐fold increase in scratch closure. To isolate cell migration from the effects of cell proliferation, cell monolayers were pre‐incubated with 5, 10 and 20 μg/ml of Mitomycin C (MMC), which is a potent inhibitor of cell proliferation. This resulted in a large decrease in the leading front of scratch closure, which indicates that PR stimulated cell mitogenesis. However, irrespective of MMC pre‐treatment, PR stimulated a motogenic response. These results provide evidence of possible mechanisms by which platelets could influence bone regeneration.