Establishment and evaluation of breast cancer bone metastasis on the immunosuppressed mice

Objective To establish the immunosuppressed mice model of bone metastasis from breast cancer,thus to evaluate this model via behavior,imaging,nuclear medicine,and pathological observation.Methods Twenty female mice were randomly divided into 2 groups:control group and model group.Immunosuppressed mice were constructed with cyclophosphamide and dexamethasone injection.Control group mice were injected with normal saline at the same time.Human breast cancer MDA-MB-231 cells in logarithmic phase were transplanted into the right tibia in all mice.Tumor formation time and rate were recorded,while the pathological and imaging observation was carried out.Results Tumor formation was found in 8 immunosuppressed mice.On Day 5 after operation,tumor could be touched.Bone destruction was found by image examination,while abnormal focus in right tibia was observed via PET/CT and reduction in right tibia BMD.Meanwhile,serum alkaline phosphatase was significantly increased(P 0.01).Bone damage by tumor was also observed under the microscope.No tumor formation was found in control group.Conclusion This breast cancer bone metastasis model overcomes cumbersome breeding,poor tolerance,short survival time and other shortcomings in nude mice;providing a simple and high efficacy mouse model of bone metastasis from breast cancer.