To investigate the protective effect of Sijunzi Tang on immune system damage and bone marrow damage in mice caused by ionizing radiation.

Eighty BALB/c mice aged 6–8 weeks were randomly by random number table method divided into normal control group, radiation group, and the other three groups of Sijunzi Tang at different dosages of 0.75, 2.25 and 6.75 g/kg, respectively. Radiation-damaged mouse model was single-irradiated by 3.5 Gy ⁶⁰Co γ-rays. The spleen index, apoptosis of spleen cells, and the micronucleus rate of polychromatic erythrocyte were detected.

At 7 d after irradiation, decrement of mouse spleen index were inhibited (t=-3.282, -6.386, -3.901, P<0.05) by all three dosages of Sijunzi Tang. Sijunzi Tang at the dosage of 2.25 g/kg reduced the early apoptosis of spleen cells at 3 d after irradiation (t=4.143, P<0.05) as well as late apoptosis of spleen cells at 7 d after irradiation (t=2.413, P<0.05). The micronucleus frequency of polychromatic erythrocyte was reduced by Sijunzi Tang dose-dependently (t=2.914, 3.285, 8.000, P<0.05).

Sijunzi Tang could alleviate the damage caused by ionizing radiation and improve mouse immune and hematopoietic function through increasing spleen index, reducing spleen cells apoptosis and micronucleus frequency of polychromatic erythrocyte.

Sijunzi Tang; Ionizing radiation; Spleen; Apoptosis; Micronucleus