Erythropoietin (Erythropoietin, EPO) is also a colony stimulating factor, which can promote the expansion and differentiation of bone marrow erythroid colony forming units, and cooperate with other cell growth factors to promote cell proliferation and differentiation, inhibit cell apoptosis, and increase the number of red blood cells. . After the EPO cDNA was successfully cloned in 1985, rhEPO has gradually been widely used in the treatment of various anemia diseases. At present, the indications