Comparison of immunosuppression induced by different doses of cyclophosphamide in normal mice

objective To investigate the effects of cyclophosphamide (CY) on the immunosuppression in normal mice. Methods Different doses of CY were given to normal mice at different time-points, and the effects of CY on immunological indices of mice were observed. Results After injection of CY at doses of 20, 80, 100 mg/kg, all mice showed various degrees of immunosuppression. The rate of lymphocyte transformation, the levels of NK cell activity, the number of total T cells, and the rates of Th/Ts were significantly descended in low-dose treated mice ( P 0.01) and high-dose trea-ted mice ( P 0.05). But there was no significant difference between high-dose treated mice (80 mg/kg for 5 d) and the untreated control mice ( P 0.05). Conclusion Immunosuppressive model has been established by intraperitoneal injection of CY at the doses of 20, 80, and 100 mg/kg, and the dose of 80 mg/kg for 3 d was the best dose for establishing the model.