Enhanced cellular responses of human bone marrow stromal cells cultured on pretreated surface with allogenic platelet-rich plasma.

The principal objective of this study was to evaluate the effects of surface pretreatment with platelet-rich plasma (PRP) on the cellular functions of human bone marrow stromal cells (hBMSCs). The surfaces of tissue culture plates (TCPs) were pretreated by adding PRP followed by centrifugation to bring platelets closer to the surface, followed by incubation for 60 min at 37°C. Then, hBMSCs were seeded onto TCP and TCP pretreated with PRP (TCP-PRP), followed by culture in osteogenic medium. Cell attachment, proliferation, and osteogenic differentiation were evaluated. Field emission scanning electron microscope (FE-SEM; JSM-7401F, JEOL Ltd., Japan) observations were conducted. The attachment of hBMSCs was significantly lower on TCP-PRP than on TCP. However, when the cell numbers were normalized with those observed on day 1 of culture, cellular proliferation on 5 days was significantly higher on TCP-PRP. Alkaline phosphatase activity, an index of early phase of osteoblastic differentiation, was significantly higher on TCP-PRP on day 14. Calcium deposition amount, an index of terminal osteoblastic differentiation, was also significantly higher on TCP-PRP on days 14 and 21. The results of von Kossa staining confirmed that, on day 21, the area of mineralized nodules was significantly larger on TCP-PRP. FE-SEM observation demonstrated that activated platelets and fibrin network covered the surface after PRP treatment. An increase in the number of hBMSCs and their cellular products was evident on the FE-SEM observation, and the fibrin network remained on day 21. Our results demonstrate that a PRP-treated surface enhanced early proliferation and late osteogenic differentiation of hBMSCs.