Reproduction and appraisal of an animal model of acute myelomonocytic leukemia in the CB6F1generation mice

Hong-li ZUO, En-lan PENG, Tie-qiang LIU, Shan HUANG, Yu-fang LI, Xiao-lan YAO, Shi-chen SHANG, Hui-sheng AI

Abstract


Objective To reproduce an acute myelomonocytic leukemia M4(AML-M4)animal model with the CB6F1generation mice.Methods The CB6F1(BALB/c C57BL/6)mice were inoculated intravenously with different amounts(1×106,2×106,5×106,1 ×107)of WEHI-3cells,a cell line of myelomonocytic leukemia.The correlation between the animal survival and the inoculated amount was analyzed.The mice,inoculated with 1×106 cells,were selected for observation of leukemia onset,and sampled for routine blood test.Four weeks after inoculation,the peripheral blood was collected from moribund mice,morphological observation was made in blood smears,and immunophenotype and major histocompatibility complex(MHC)was determined;the marrow cells were collected for morphological observation,and immunochemical and karyotype analysas were made.The liver,spleen,kidney,lung,heart and brain were obtained for pathological observation.The results of all the observations and determinations were then comprehensively analyzed to evaluate the authenticity of the established AML-M4mice model.Ara-C,in a dosage of 50mg/kg or 100mg/kg,was intraperitoneally injected to the model mice for observation of the disease course and survival of the animals,and to evaluate the sensitivity of model mice to the chemotherapeutics.Normal mice were selected to serve as control in all the experiments.Results Mice inoculated with different amount of WEHI-3cells died of leukemia 17to 33days after inoculation,and a negative correlation between the inoculated amount and the survival time of animals was observed(r=-0.936,P < 0.01).Those inoculated with 1×106 cells survived for 25~33(28.50±1.87)days.Four weeks after inoculation,the WBC counts of peripheral blood increased obviously with a peak value of 81×109/L,in the moribund leukemic mice,which was significantly different from that of normal control(P < 0.05).Leukemia cells with larger size and irregular shape were observed in the blood smear.A large number of primary and immature cells were found in the marrow smear,and peroxidase(POX),specific esterase(SE),nonspecific esterase(NSE)and sodium fluoride(NaF)inhibition test were all positive,which were consistent with the characteristics of AML-M4.Diffuse infiltration of large number of leukemia cells was observed in multiple organs.The chromosomes of marrow cells were hyperdiploids.CD4+/CD8+in peripheral blood declined,and C-KIT and MAC-3were expressed in a larger number of cells compared with the normal animals(P < 0.05).The percentage of MHC with H2Kb-H2Kd+phenotype was increased,which became the major phenotype in the moribund mice.The model mice were sensitive to Ara-C,which may prolong the survival period of leukemic mice,especially with a dosage of 100mg/kg(P < 0.05).Conclusion A murine model of AML-M4has been successfully reproduced by intravenous inoculation of WEHI-3cells.

Keywords


leukemia,myelomonocytic,acute; WEHI-3cell; model,animal

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