Low oxygen tension induces the effect of EPO and its tissue-protective analogues on BAECs proliferation. BAECs were treated with EPO, CEPO, pHBSP and scr-pHBSP at different concentrations (0, 1 and 10 ng/mL) then incubated under 21% oxygen (left panel) or 5% oxygen (right panel) for 24 h. The effect of EPO (A,B), CEPO (C,D), pHBSP (E,F) and scr-pHBSP (G,H) on BAECs proliferation was analyzed by trypan blue exclusion method. Each data point represent mean ± SEM (n = 3), *p < 0.05 and ** p < 0.01.