| Objective: Establishment of new SAA mouse model mediated by immune mechanism.Methods: Female mice of the offspring B6D2F1(hereinafter referred to as F1)produced by the cross between DBA/2 male mice and C57BL/6 female mice were used as recipient mice,and their whole bodies were uniformly irradiated with sub-lethal dose(5 Gy)of X-rays,within 4-6 hours after irradiation,intraperitoneal injection of the lymph node mononuclear cell suspension of B6 female mice of the same age,12 days later,the SAA mouse model was successfully established.The F1 female mice of the same age were randomly divided into the following groups:(1)Normal group: normal F1 female mice of the same age.(2)AA group: SAA mice prepared by irradiation and allogeneic lymphocyte infusion.(3)TBI group: F1 female mice received only the same dose of X-ray irradiation.(4)ALI group: F1 female mice received only intraperitoneal injection of B6 female mouse lymph node mononuclear cell suspension.(5)PBS group: F1 female mice were intraperitoneally injected with an equal volume of PBS.The physical signs,blood routine,bone marrow biopsy,and the distribution of CD4+ and CD8+ T lymphocytes in bone marrow,peripheral blood and spleen were compared among the five groups of mice.Results:(1)The mice in the AA group developed typical severe aplastic anemia symptoms one after another after the irradiation and allogeneic lymphocyte infusion.Taking the 12 th day as the detection time point,the blood routine of the mice in this group showed that WBC,RBC,HB,and PLT were significantly less than those in Normal group and ALI group(P < 0.05);T lymphocyte subsets detection showed that the proportion of CD4+ and CD8+ T cells in spleen,bone marrow and peripheral blood of mice in the AA group was significantly higher than those in the Normal group,but the increase in CD8+ T lymphocytes was more significant(P <0.05).Bone marrow biopsy showed that the typical hematopoietic tissue failure in the bone marrow of mice in AA group.There were no obvious signs of graft-versus-host(a GVHD)of lymphocyte infiltration and tissue destruction in target organs such as lung,liver and small intestine by histopathological examination.(2)The mice in TBI group were in poor general condition on the 3rd day after total-body irradiation,and gradually returned to normal.Taking the 12 th day as the detection time point,the counts of WBC,PLT and NE of the mice in TBI group were significantly lower than those of the normal mice(P < 0.05),However,RBC and HB were not significantly different from normal mice,which did not conform to SAA peripheral blood findings.There was no obvious T lymphocyte infiltration in the bone marrow of the mice in the TBI group,and the bone marrow biopsy showed no signs of bone marrow failure.(3)The mice in the ALI group were in good condition within 0-12 days.Taking the 12 th day as the detection time point,there was no statistical difference between the blood routine indexes and the normal mice,and there was no obvious T lymphocyte infiltration in the bone marrow of the mice.Conclusion: The new mouse model of SAA mediated by immune mechanism has typical severe aplastic anemia,and the peripheral blood cells and bone marrow hematopoietic cells are significantly reduced.The analysis of T lymphocyte subsets in peripheral blood,bone marrow and spleen of model mice showed that the proportion of CD8+ T lymphocytes was significantly increased.Except for the bone marrow,there was no obvious a GVHD damage in important T cell target organs such as the small intestine,lung,and liver,which is consistent with the performance of human aplastic anemia. |
