The Analysis Of Related Factors Affecting The Activity Of Platelet-rich Plasma

Objective:The activity of platelet-rich plasma (PRP) correlates closely with the platelet count and activity. The purpose of the present study was to investigate the effect of different centrifugation and storage methods on concentration and activity of platelet. Additionally, the effect of different activators on platelet clotting and releasing of growth factor of PRP was measured. The best centrifugation and storage method and the activator were suggested in order to provide theoretical and experimental evidence for following animal experiment and clinical application.Methods:PRP was prepared through twice centrifugation method. It was divided into four groups. First method is centrifugation at 200g for 10 minutes and further 200g for 10 minutes. The second is centrifugation at 200g for 10 minutes and further 1200g for 10 minutes. The third is centrifugation at 1200g for 10 minutes and further 200g for 10 minutes. The last method is centrifugation at 1200g for 10 minutes and further 1200g for 10 minutes. Counting of the platelet and percent recovery of platelet were performed. Concentration of P-selectin was measured and normalized by platelet counting. After PRP was stored by 22℃and -80℃for 24h, counting of the platelet, percent recovery of platelet and concentration of P-selectin were measured. Chitosan, bovine thrombin and thrombin receptor agonist peptide(TRAP)were used to prepare PRG. PRG clotting time, clot retraction ratio and concentration of released TGF-β1 and PDGF were measured. Statistical analyses were performed by one way ANOVA using SPSS11.0.Results:Platelet counts in PRP prepared by four different methods were increased with respect to venous blood platelet counts, which were 4.21,4.94,4.12,4.72 times respectively. Percent recovery of platelet by the second method was observed to be significantly higher when compared to first and third methods (P<0.01). No significant difference in concentration of P-selectin normalized by platelet counts in PRP was observed between second centrifugation method and forth method (P>0.05), whereas significant difference was observed when compared to other two methods (P<0.01). No significant difference in platelet count in fresh and stored PRP prepared by the second centrifugation method was observed (P>0.05). No significant difference in concentration of P-selectin normalized by Platelet counts in PRP was observed between fresh PRP and PRP stored in 22℃(P>0.05), whereas significant difference was observed when compared to PRP stored in -80℃( P<0.05). The most rapid polymerization of PRP took place with the addition of bovine thrombin. The bovine thrombin group was observed to cause more considerable retraction at 1, 2, and 4 hours when compared to chitosan and TRAP groups (P<0.05). But at 24 hours no significant difference in clot retraction among three groups was observed (P>0.05). No significant difference in concentration and total amount of TGF-β1 released from PRG activated by three different activators was observed (P>0.05). The concentration and total amount of PDGF was highest in TRAP group, and significant difference was observed when compared to other two groups(P<0.05).Conclusion:It was concluded that PRP prepared by centrifugation at 200g for 10 minutes and further 1200g for 10 minutes provide the higher platelet count and percent recovery of platelet and decrease centrifugation-induced platelet aggregation. It may be an efficient method for PRP preparation. PRP stored in 22℃has the higher platelet count and lower storage-induced platelet aggregation. It may be a suitable temperature for PRP storage. Simultaneously, TRAP may be one of safe and effective activator of PRG which can provide more working time and growth factor releasing.