Erythropoietin (EPO) is a growth factor produced in the kidneys that stimulates the production of red blood cells. It works by promoting the division and differentiation of committed erythroid progenitors in the bone marrow. Epo additionally plays a tissue protective role in ischemia by blocking apoptosis and inducing angiogenesis. To test the effect of EPO on cell proliferation, TF-1 cells were seeded into triplicate wells of 96-well plates at a density of 8,000 cells/well with 2% serum standard 1640 which contains various concentrations of recombinant dog EPO. After incubated for 48h, cells were observed by inverted microscope and cell proliferation was measured by Cell Counting Kit-8 (CCK-8). Briefly, 10 µl of CCK-8 solution was added to each well of the plate, then the absorbance at 450 nm was measured using a microplate reader after incubating the plate for 4 hours at 37 ℃. Proliferation of TF-1 cells after incubation with EPO for 48h observed by inverted microscope was shown in Figure 1. Cell viability was assessed by CCK-8 assay after incubation with recombinant dog EPO for 48h. The result was shown in Figure 2. It was obvious that EPO significantly increased cell viability of TF-1 cells. The ED50 is 17 ng/ml.

Figure 2. Cell proliferation of TF-1 cells after stimulated with recombinant dog EPO.