The aim of this study was to investigate the protective effects of three glycosides (rhodioside, ciwujianoside-B and astragaloside IV) on the hematopoietic system in the mice exposed to γ-rays, and to examine the possible mechanisms involved. Mice were pretreated with the glycosides (40 mg/kg, i.g.) daily for 7 days prior to radiation. The survival of mice pretreated with three glycosides after total body irradiation (6.0 Gy) was examined. Peripheral blood leucocytes and endogenous spleen colony counts, colony-forming unit-granulocyte macrophage assay, analysis of DNA content and apoptosis rate determination were performed to evaluate the effects of the three glycosides on hematogenesis. The fragmentation of double-stranded DNA in lymphocytes was detected by the comet assay. The changes in cell cycle were analysed by flow cytometry. Furthermore, the expression levels of Bcl-2, Bax and nuclear factor-kappa B (NF-κB) were measured by western blot and the electrophoretic mobility shift assay. The results showed that pretreatment with all of the glycosides improved survival time and increased the number of leucocytes, spleen colonies and granulocyte-macrophage colonies in mice exposed to 6.0 Gy γ-radiation. Rhodioside showed more protective efficacy than both ciwujianoside-B and astragaloside IV. All three glycosides significantly increased the proliferation abilities of bone marrow cells, and decreased the ratio of cells in G(0)/G(1) phase. Further analysis showed that these three glycosides were able to decrease DNA damage and the increment in the Bax/Bcl-2 ratio induced by radiation. In summary, the three glycosides showed radioprotective effects on the hematopoietic system in mice, which was associated with changes in the cell cycle, a reduction in DNA damage, and down-regulation of the ratio of Bax/Bcl-2 in bone marrow cells exposed to radiation.
Copyright © 2010 John Wiley & Sons, Ltd.