Effects of erythropoietin on immune function of tumor-bearing mice

Objective:To study the effects of erythropoietin(EPO) on immune function in a murine melanoma model.Methods:C57BL/6 mice were randomly divided into 3 groups: normal control group,saline-treated group and EPO-treated group.Mice of saline-treated group and EPO-treated group were inoculated with melanoma cell B16.The changes of red blood cell(RBC),hemoglobin(Hb),hematocrit(Hct) and white blood cell(WBC) in peripheral blood,spleen index were observed.The subpopulations of CD4+ and CD8+ T-cell in mice spleen was performed by flow cytomery.Serum concentrations of interleukin(IL)-2 and tumor necrosis factor(TNF)-α of 3 groups was measured by ELISA.Results:A significantly greater reduction in the levels of RBC,Hb and Hct in peripheral blood was observed in saline-treated mice compared to the normal control mice(P 0.05).EPO treatment increased the levels of RBC,Hb and Hct in peripheral blood and spleen index in tumor-bearing mice(P 0.05).The levels of WBC in peripheral blood was not different in 3 groups(P0.05);CD4+ T-cell percentage and CD4+/CD8+ ratio of spleen cell was significantly decreased in tumor-bearing mice compared to the normal control group(P 0.05).CD4+ T-cell percentage of mice spleen was not different(P0.05),but CD8+ T-cell percentage was significantly decreased leading to increase of the CD4+/CD8+ ratio in EPO-treated group compared to the saline-treated group(P 0.05);the serum concentrations of IL-2 and TNF-α was significantly decreased in tumor-bearing group compared to the normal control group(P 0.05).The concentration of IL-2 was significantly increased in EPO-treated group compared to the saline-treated group(P 0.05),while that of TNF-α was not different in both study groups(P0.05).Conclusion:These results suggest that EPO treatment can correct the anemia,and also improve immune function in tumor-bearing mice by increasing the CD4+/CD8+ ratio and IL-2 concentrations of peripheral blood.