Abstract:

OBJECTIVE: To evaluate the preventive and therapeutic effects of Sijunzi decoction on damage from ionizing radiation in hematopoietic and immune systems. METHODS: CCK-8 assay kit was used to detect the toxic effect of AHH-1 cells which were treated with different dosages (0,60,120,600,1 200 μg/mL) of Sijunzi decoction extract for 48 h. In addition,the survival rate of AHH-1 cells which were pretreated with different dosages (0,0.04,0.2,1,25,120 μg/mL) of Sijunzi decoction for 2 h and irradiated with 4.0 Gy ⁶⁰Co γ-rays was investigated. One hundred and sixty BALB/c mice aged 6-8 weeks were divided by random number table method into normal control group,radiation group,and three groups of Sijunzi decoction at dosages of 0.75,2.25 and 6.75 g/kg,respectively. Radiation-damaged mice model were individually-irradiated with 3.5,5.5 Gy γ-rays,respectively. The following activity indexes were investigated:the count and percentage of peripheral lymphocytes,thymus index,survival rate and average survival time in 30 d. RESULTS: Compared to the radiation group,the survival rate of irradiated AHH-1 cells were increased greatly by Sijunzi decoction at the dosage of 120 μg/mL (P < 0.05). At 3 d after irradiation,the count and percentage of peripheral lymphocytes were promoted significantly (P < 0.05) by Sijunzi decoction at the dosage of 2.25 g/kg in mice. The percentage of peripheral lymphocytes was increased significantly (P < 0.05) by Sijunzi decoction at the dosage of 6.75 g/kg,also the count of peripheral lymphocytes was increased. At 3 and 7 d after irradiation,the thymus index was increased significantly (P < 0.05) by Sijunzi decoction at the dosage of 6.75 g/kg. Besides,the survival rate was increased (P < 0.05) and the mean survival time was prolonged significantly (P < 0.05) by Sijunzi decoction at the dosage of 6.75 g/kg. CONCLUSION: Sijunzi decoction could alleviate the ionizing radiation-induced damage,improve mice immune and hematopoietic function,by means of increasing the count and percentage of peripheral lymphocytes and the thymus index. On the other hand,Sijunzi decoction can also improve the 5.5 Gy-irradiated mice's survival rate. Accordingly,Sijunzi decoction might be developed into a new drug for radiation protection.

Key words: Sijunzi decoction, ionizing radiation, lymphocytes, thymus, survival rate