The Effects Of Low Dose Radiation Combined With Cyclophosphamide On Tumor Apoptosis,Cell Cycle And Proliferation Of Bone Marrow In The Tumor-Bearing-Mice

Objective To study the effect of low dose radiation (LDR) combined with cyclopho - sphamide on tumor apoptosis, cell cycle and proliferation of bone marrow in the tumor-bearing-mice.Methods Kunming stain male mice were implanted the SI 80 sarcoma cell in the left hint inguen subcutaneously as an experimental in situ animal model. 5 days after implantation , the mice were given 75mGy whole-body r -ray radiation,CTX (300mg/kg)was given by ascitic injection 36 hour after LDR. In the followed 8-11 day, above methods were repeated. All mice were sacrificed to measure the tumor volume, tumor cell apoptosis, cell cycle and proliferation of bone marrow was analyzed by flow cytometry.Result The tumor growth was significantly slowed down on above treated groups. The tumor cells were arrested in Gl phase on CTX and CTX+LDR group, the latter more significantly than former. Concentration of bone marrow and PI of CTX+LDR group mice is higher than CTX. group mice, although concentration of bone marrow of CTX and CTX+LDR group mice is much lower than normal mice.Conclusion low dose radiation combined with Cyclophosphamide could cause a more significant G1-phase arrest than pure Cyclophosphamide and increase anti-tumor ability markedly. At the same time LDR significantly protect bone marrow of organism which provides practical evidence for thecombination of LDR and chemotherapy. It not only proves the LDR's anti-tumor ability, but also provides practical evidence of clinical application to the combined treatment of radiotherapy, chemiotherapy and LDR .