Effects of Platelet-Rich Plasma on Proliferation and Osteogenetic Activity of Marrow Mesenchymal Stem Cells in Vitro

Objective: To study the effects of platelet-rich plasma (PRP) on the proliferation and osteogenetic activity of the marrow mesenchymal stem cells (MSCs) cultured in vitro to elucidate the cellular and molecular mechanism by which PRP accelerates bone repair.

Methods: The human MSCs were cultured in vitro and randomly divided into the experimental group (n = 9) and control group (n = 9). In the experimental group, the MSCs were interfused with PRP (10 microl/ml culture media). The proliferation ability of the cells was tested by flow cytometry and MTT, the osteogenetic activity by alkaline phosphatase (ALP) measuring and tetracycline fluorometry, and cbfa1 mRNA expression by reverse transcript-PCR.

Results: PRP could stimulate the MSCs proliferation. The flow cytometry assay showed that the MSCs proportion of S period of the experimental group significantly increased 14.5+/-0.4 in comparison with that of the control group 7.2+/-0.5 (P<0.01) after 24 hours. MTT value showed that MSCs proliferated to platform period earlier in the experimental group than in the control group. There was a significant increase in ALP activity of the experimental group 7.79+/-1.98, 9.51+/-2.31 and 14.03+/-3.02 when compared with that of the control group 2.06+/-0.77, 2.84+/-0.82 and 2.58+/-0.84 after 3, 6 and 9 days (P<0.05). The number of mineral nodes increased. Reverse transcript-PCR showed that the expression of cbfa1 mRNA were elevated gradually at 2, 4 and 8 hours after interfused with PRP.

Conclusion: The effect of PRP on accelerating bone repair is related to its effects on stimulating the proliferation of MSCs, increasing the cbfa1 expression and promoting the osteogenetic activity.