Abstract: Objective To explore the effect of aluminum chloride on the erythroid differentiation of K562 cells.Methods The percentage of viable cells was determined by trypan blue staining.The percentage of cells containing hemoglobin was estimated by staining with benzidine.The expression of transferrin receptor CD71 on the surface of K562 cells was estimated by flowcytometry after staining with FITC-conjugated anti-CD71 antibody.Results After the K562 cells were treated with Al(50-150 μmol/L) for 24,48,or 72 hours,the growth of K562 cells showed a concentration-dependent inhibition.When K562 cells were exposed to Al(50-150 μmol/L) for 48 hours,the hemin-induced hemoglobin synthesis showed an obvious concentration-dependent inhibition.The exposure to aluminum ions(100 μmol/L) for 48 hours caused an up-regulation of CD71 protein on the cell surface.Conclusion Aluminum chloride could inhibit hemin-induced erythroid differentiation of the K562 cells,suggesting that K562 cells could be used as a in vitrol model to research the mechanisms of the erythropoietic toxicity of aluminum.