[Effect of Storage Time on Cumulation of Platelet-related Growth Factors in the Supernatant of Leukoreduced Packed Red Cells and Tumor Cell Proliferation In Vitro].

Objective:To investigate the effect of storage time on accumulation of platelet-related growth factors in the supernatant of leukoreduced packed red blood cells(LR-pRBC) and on tumor cell proliferation in vitro.Methods:LR-pRBC were quartered and stored at 2 ℃ —6℃.The supernatant of pRBC was obtained by centrifugation with 1 006×g for 10 min at day 0,14,21 and 35 d.The enzyme-linked immunosorbent assay(ELISA) was used to detect the expression of platelet-derived growth factor(PDGF) and vascular endothelial growth factor(VEGF).After HepG_2 cells was cultured with the supernatant of LR pRBC at day 0 and day 35 together for 48 hours,methylthiazoliltetracolium(MTT) method was used to measure the proliferation of tumor cells in vitro.Results:The concentrations of 2 cytokines were still increased with the storage time prolonging.As compared to LR-pRBC at day 0[611.84(95%CI,356.45-867.23) pg/ml],the level of VEGF reached 900.16(95%CI,552.26- 1248.07) pg/ml(P 0.05).There was a similar tendency in PDGF level with less increment in the supernatant of LR pRBC at day 35[2.23(95%CI,0-5.37) ng/L vs 5.66(95%CI,0-12.48),P =0.073],but there was no significant statistical difference.Likewise,in vitro study of HepG_2 cell proliferation showed that the LR-pRBC at day 35 promoted more proliferation of tumor cells with OD value 0.40(95%CI,0.38- 0.42)(P 0.05).Conclusion:The residual platelets in LR-pRBC were activated,disintegrated and released the dense granules and α-granules which induce the accumulation of VEGF and PDGF.It seemed that the supernatant of LR-pRBC promoted the proliferation of tumor cells in vitro.