Objective   To study the effects and possible mechanisms of zinc on the C-ray induced irradiation damage of the bone marrow(BM)hematopoietic cells in mice.

  Methods   The BM cells(BMC)were separated from mice and were suspended in RPMI 1640 mediums.Zinc was added to the mediums, whose final concentrations in the mediums were 20, 200, 400, 800μmol/L respectively.Then the cells were irradiated by ⁶⁰Coγ-ray, the dose was 5Gy.16 hours later, the number of BM karyote and the contents of DNA of BMC were measured.By flow cytometry(FCM)and immunihistochemistry technique, the rates of cell apopotosis, the changes of the cell cycle and the expression of genes were examined respectively.

  Results   After irradiation, the number of BM karyote and the contents of DNA were decreased; the rates of cell apoptosis were increased.BM cells were blocked in Sphase, lower expression of bcl-2 protein and higher expression of p21 protein were observed in BM cells.When Zn²⁺ were added to the cell cultures before irradiating, the number of BM karyote and the contens of DNA were increased; the rates of cell apoptosis were decreased.The block of the cell cycle was improved significantly, the expression of bcl-2 protein was increased and the expression of p21 protein was decreased.

  Conclusion   Zinc may protect mice BM cells against radiation damage in vitro by its effects on cell apoptosis, cell cycle and expression of genes.