Study Of Platelet-rich Plasma In Promoting Bone Regeneration As Autologous Source Of Growth Factors

Object:Platelet-rich plasma (PRP) were abtained by both the original and the improved methed. We evaluated the samples by testing the concentration of platelet and TGF-β1. Human osteobiast were cultured and identified, and the effect of human serum derived from PRP on the biological function of human osteobiast was evaluated in vitro. Furthermore, the osteogenetic ability of PRP were inspected in vivo, and provided a stronger foundation to its clinical application. Methods:1. Whole blood was collected from 8 healthy donors, and then PRP was separated by both the original method and the improved method. Samples were evaluated by platelet count and sterile test. The level of TGF- β1 in serum derived from PRP was assayed by enzyme-linked immunoassay (ELISA).2. PRP and PPP were obtained by improved method and activated to get serum. The level of TGF- β1 and PDGF-AB in surum derived from PRPor PPP were assayed by enzyme-linked immunoassay (ELISA). Cultured human osteoblast cells were treated with 5% surum derived from PRP, 5% surum derived from PPP and serum-free Dulbecco's modified Eagle medium (DMEM). Cellular mitogenic activity was evaluated by thiazoly blue (MTT) colorimetric assay at the 24th, the 48th, the 72nd and the 96th hour.3. Four equal 8 mm diameter bone defects on rabbit cranium were created and, at the same time, autologous PRP was obtained by the improved method. PRP was activated by thrombin and mixed with hydroxyapatite/tricalcium phosphate(HA/rCP). These cranial defects were grafted with HA/TCP alone, HA/TCP and collagen membrane, HA/TCP combined with PRP, HA/TCP combined with PRP and collagen membrane. The defects were evaluated by radiography, histology, immunolustochemistric inspection and histomorphometric analysis performed at 2,4, 8 weeks.Result:1. The end product of the improved method was sterile and has both a higher platelet count in PRP (p<0.05) and a higher level of TGF-& I in serum derived PRP (p<0.05). The stability analysis proved the improved methed was more reliable.2. The proliferation of human osteoblast was promoted after treated with surum derived from PRP To compared with serum derived from PPP, the differences in absorbency value were significant at the 48th, 72nd and 96th hour (p<0.05). The proliferation of osteoblast almost stoped in serum-free medium, and the differences, compared with other groups, were significant3. The results showed a significant increase in osteogenetic ability when HA/TCP combined with PRP and/or using collagen membrane.Conclusion:High quality of PRP can be achieved by the improved method and serum derivedfrom PRP was capable of up-regulating the proliferation of human osteoblast in vitro.PRP in combination with HA/TCP can accelerate the new bone formation in bone defectand using GBR membrane simultaneously got the best bone regeneration. So using PRPas autologous source of growth factors maybe considerable use in clinic.