[The effects of different activators on the release curve of human platelet-rich plasma]

Objective: To compare and analyze the effects of different activators on the release curve of TGF-β(1) and PDGF-AB in platelet rich plasma(PRP). Methods: A total of 36 ml peripheral venous blood was obtained from 10 healthy adult volunteers, and the PRP was made by secondary centrifugation. The platelet activator was made by bovine thrombin 1 000 U in 1 ml 10% calcium chloride solution. The Thrombin-PRP group was made by PRP and the activator in a ratio of 10∶1.The Calcium chloride-PRP group was made in a ratio of 10∶1 by PRP and 10% calcium chloride solution instead. The fresh whole blood(whole blood group) and inactived PRP(PRP group) were used as the control groups. The 4 groups were incubated in warm water of 37 ℃ for 0, 1, 8, 24,72 and 168 h. A quantitative sandwich enzyme-linked immunosorbent assays(ELISA) was used to examine the amount of TGF-β(1) and PDGF-AB in different time points of each group. The release curves of TGF-β(1) and PDGF-AB were based on afore-mentioned data, and then comparisons of the release curves of TGF-β(1) and PDGF-AB in different groups were performed by repeated measurement variance analysis. Results: (1)The levels of TGF-β(1) and PDGF-AB in the whole blood group and the PRP group continued to increase within 168 h. PRP immediately formed into a gel after mixture with thrombin combined and calcium chloride, and the concentrations of TGF-β(1) and PDGF-AB reached the peak in 1 h after activation; increased from (42±21)ng/ml and (77±18)ng/ml to (84±21)ng/ml and (124±35)ng/ml, respectively, and then decreased gradually. The release curve was direct and rapid. The PRP became a gel state in approximate 1 h after mixture with calcium chloride, and the concentrations of TGF-β(1) and PDGF-AB were slowly rising and remained high at 168 h. (2)The AUC(0-168h) of TGF-β(1) and PDGF-AB in the PRP group was higher than that in the whole blood group (all P<0.05) , and the AUC(0-168h) of TGF-β(1) in the Calcium chloride-PRP group was higher than that in the Thrombin-PRP group(Z=-2.26, P<0.05).However, there was no significant difference in the AUC(0-168h) of PDGF-AB between the Calcium chloride-PRP group and the Thrombin-PRP group(Z=-1.512, P=0.131). Conclusion: Using calcium chloride as activator can get a higher release concentration of TGF-β(1) and PDGF-AB and a longer release time, with the largest area under the curve.