ABSTRACT
Platelet-Rich Plasma [PRP] is a concentration of human platelets in a small volume of plasma. It has been shown that effects of this product on various cell types is due to synergistic effects of some proteins of platelet alpha granules as platelet growth factors. The purpose of this study is definition of the more efficient platelet product, with higher protein and growth factor concentration for using in various applications. In this study, platelet-rich plasma was isolated by apheresis method. Activated Platelet-rich Plasma [AP] was prepared by platelet activation by thrombin and calcium chloride. Platelet Supernatant [PS] and Platelet Lysate [PL] preparation was performed by high speed centrifugation [900 g], and freezing and thawing of platelet rich plasma, respectively. The growth factors and protein concentrations in these platelet products were measured by ELISA and Bradford methods, respectively. Platelet concentration of Platelet-rich Plasma was 1.066x10[9] +/- 0.15x10[9] /ml [Mean +/- SD]. According to the results, concentrations of PDGF, TGF-beta, FGF, EGF and protein were few in Platelet Supernatant [0.24 +/- 0.03 ng/ml, 4.5 +/- 0.4 ng/ml, 0.8 +/- 0.06 pg/ml, 2.6 +/- 0.3 pg/ml and 460 +/- 6 mg/ml, respectively] and significantly increased by platelet activation [23.0 +/- 2.1 ng/ml,19 +/- 3.0 ng/ml,7.4 +/- 1.0 pg/ml,23.3 +/- 3.0 pg/ml and 480 +/- 4 mg/ml, respectively] or freezing and thawing of PRP [18.1 +/- 1.9 ng/ml, 16.0 +/- 3.0ng/ml,10.2 +/- 1.3pg/ml,31.0 +/- 4.0 pg/ml and 490 +/- 5 mg/ml, respectively], [P<0.05]. We showed that concentration of PDGF and TGF- beta as two major platelet growth factors is significantly higher than FGF and EGF in all of three platelet products [P<0.05]. We also found that FGF and EGF concentrations are significantly higher in Platelet Lysate [10.2 +/- 1.3 and 31.0 +/- 4.0] than Activated Platelet-rich Plasma [7.4 +/- 1.0 and 23.3 +/- 3.0] [P<0.05], and TGF-beta in Platelet Supernatant [4.5 +/- 0.4], in contrast to two other platelet products, is significantly higher than PDGF [0.24 +/- 0.03] [P<0.05]. Preparation of Platelet-rich Plasma by apheresis method, gives a high platelet count. Protein extraction by PRP activation yields a higher concentration of two major factors [PDGF and TGF-beta], in spite of higher amounts of protein, FGF and EGF in Platelet Lysate. More studies are needed to define the relation between higher growth factor concentration or protein content and effects in various applications