Auto-platelet rich plasma gel stents produced with different methods promote proliferation of adipose-derived stem cells

Objective To study the effect of auto-platelet rich plasma (PRP) gel stents produced by centrifugation on proliferation of adipose derived stem cells (ADSCs) and release of growth factors. Methods Auto-PRP gel stents were produced by two or three centrifugations of arterial blood from New Zealand rabbits.Platelet concentration in such stents were measured.After the absolute platelet concentration in auto PRP gel stents was adjusted to 1000×10⁹/L by adding DMEM, the volume fraction of auto-PRP gel stents into which DMEM was added was adjusted to 30%, 40%, 50% and 60% of the absolute platelet concentration.Auto-PRP gel stents containing only DMEM served as a blank control group.Fluorescence-stained ADSCs were then implanted into auto-PRP gel stents and counted for 7 consecutive days.Cell growth curve was plotted.Survival rate and proliferation activity of ADSCs were analyzed by MTT colorimetry on days 2-4 and 6.TGF-β1 and collagen-Ⅱlevels in ADSCs were measured by ELISA. Results The platelet concentration in auto-PRP gel stents produced by two and three centrifugations was(1320.5±227.3)×10⁹/L and (1724.5±316.3)×10⁹/L respectively, which was 5.4-fold and 7.1 –fold higher than that in the whole blood (P< 0.05).The platelet concentration in auto-PRP gel stents produced by three centrifugations was higher than that in auto-PRP gel stents produced by two centrifugations(P< 0.05).The number of ADSCs in auto-PRP gel stents produced by two or three centrifugations reached its peak which was (1.02±0.13)×10⁴ and(1.00±0.14)×10⁴ respectively when the platelet concentration was 500×10⁹/L(P> 0.05).The proliferation activity and the number of ADSCs in auto-PRP gel stents reached their peak when the platelet concentration was 500×10⁹/L, and the TGF-β1 and collagen-Ⅱlevels were signif icantly higher when the platelet concentration was 500×10⁹/L than when the platelet concentration was lower or higher than 500×10⁹/L(P< 0.05). Conclusion The detection rate of platelets is higher in auto-PRP gel stents produced by three centrifugations than by two centrifugations.However, no signif icant difference can be found in promoting proliferation of ADSCs in auto-PRP gel stents produced by two or three centrifugations.The proliferation and activity of ADSCs reach their peak when the platelet concentration is 500×10⁹/L in auto-PRP gel stents, which maybe the optimal concentration for preparation of PRP.