Identification And Phenotypic Study Of A New Mouse Model Of Myelodysplastic Syndrome

BackgroundMyelodysplastic syndrome(MDS)is a group of heterogeneous myeloid clonal diseases originating from hematopoietic stem cells,characterized by abnormal differentiation and development of myeloid cells,manifesting as ineffective or failed hematopoiesis and refractory hemocytopenia and associated with a high risk of transformation to acute myeloid leukemia(AML)[1].However,which cells leading to malignant transformation have not been directly elucidated,because research on the disease usually focuses on the cellular mechanisms of MDS development and prevention.As is well known,animal models are powerful tools for modelling and studying human diseases and are very useful preclinical platforms for studying problems that are difficult(or impossible)to solve clinically[1].A wide range of model organisms have been used in the biological study of myelodysplastic syndrome.Currently,established MDS animal models include mice,rats and zebrafish,among others.The models are classified into genetic modification models,chemical induction models,xenotransplantation models,etc[1].Our research have establish a new mouse model of myelodysplastic syndrome(MDS).ObjectiveTo establish a new mouse model of myelodysplastic syndrome(MDS)which will be a powerful tool for the pathogenesis study,drug evaluation and treatment of MDS.Methods1.Identification of spontaneous myelodysplastic syndrome(MDS)in JUN mice(1)Record and analyze the phenotype of JUN mice;(2)Anatomical observation of mice with abnormal manifestations,including visual phenotypic analysis of all tissues of JUN,including spleen,liver,lymph nodes,etc.Then to determine the pathological changes and abnormal cell population of JUN.(3)Changes in the number and proportion of each blood cell were detected in peripheral blood,and blood smear was made to analyze the differentiation and development morphology of blood cells;(4)The bone marrow cells of JUN mice were classified and counted by flow cytometry,and bone marrow smear was made to analyze the cell group and morphology.(5)Flow analysis was performed on the characteristic antibodies of various progenitor cells to determine the abnormal progenitor cell populations.2.Spontaneous MDS in JUN mice was verified by physical and chemical methods(1)The blood cell and bone marrow cell morphology of JUN mice were compared with those of patients with MDS.(2)Anti-CD34 and myeloid peroxidase(MPO)were used to further verify that abnormal cell populations in various tissues of JUN mice were of myeloid origin.3.To preliminarily explore the genetic causes of spontaneous MDS in JUN mice and we have the incidence statisticsMDS related mutant genes were analyzed and test their expression levels in JUN mice.Pathological detection and survival of dead mice.ResultsIn the observation of JUN mice,it was found that mice of the albino JUN strain grow longer in an SPF environment,having a smooth coat and lively character,but the life span of JUN was shorter than that of C57BL/6J mice.After 6-8 weeks old JUN mice were transferred to the isolation environment for a period of time,they began to appear wrinkled yellow hair,spirit depression and other conditions successively,and even died quickly.1.JUN in the kidneys,liver,spleen and bone marrow were lesions,characterized by renal edema,liver and spleen enlargement with severe outside the medullary hematopoiesis phenomenon,at the same time the spleen lymphocytes and red blood cell proliferative lesions,lung tissue and various organizations are basophilic mononuclear lymphocytes scattered infiltration,MPO immunohistochemical analysis showed that abnormal cells are myeloid origin;2.The peripheral blood cell count showed a decrease in the number of white blood cells,including neutrophils,monocytes and lymphocytes.At the same time,the proportion of immature white blood cells increased,the morphology of neutrophils was abnormal,and various abnormal blood cell types were observed in the blood smear.3.Flow analysis results of bone marrow showed that the number of pluripotent stem cells in blood cell progenitor group increased significantly,while the number of cells in each differentiation and development stage of B cells decreased significantly.4.Compared with peripheral blood cell morphology of MDS patients,Pseudo-Pelger-Huet cells were found to be characteristic of MDS.A pattern of cell development consistent with that seen in patients with MDS was also found in bone marrow cells.5.Anti-CD34 and MPO immunohistochemical results showed that CD34+cells and MPO positive cells increased significantly in all tissues.6.Gene sequencing analysis showed that the mutation of Rps14 gene in JUN mice whose expression was significantly reduced in spleen tissue.7.Our analysis of all dead Jun mice found an 86%probability of progression to AML.We also measured the survival of Jun mice,and the average life span was about 279 days.Conclusions1.The differentiation and development of multipotent progenitor cells(MPP)in bone marrow of Jun mice were blocked and increased significantly,so,the number of leukocyte groups in peripheral blood decreased.2.The infiltration of abnormal cells in tissues of Jun mice was from the myeloid orgin,and the cloning of primitive hematopoietic cells was increased.3.Jun mice suffer from spontaneous MDS,the mutation of Rps14 is likely to be its genetic cause.4.The incidence of MDS in Jun mice was high,and 86%of them could progress to AML.