Defective fetal liver erythropoiesis and T lymphopoiesis in mice lacking the phosphatidylserine receptor

Clearance of apoptotic cells by macrophages is considered important for prevention of inflammatory responses leading to tissue damage. The phosphatidylserine receptor (PSR), which specifically binds to phosphatidylserine (PS) exposed on the surface of apoptotic cells, mediates uptake of apoptotic cells in vitro, yet the physiologic relevance of PSR remains unknown. This issue was addressed by generating PSR-deficient (PSR(-/-)) mice. PSR(-/-) mice exhibited severe anemia and died during the perinatal period. In the PSR(-/-) fetal livers, erythroid differentiation was blocked at an early erythroblast stage. In addition, PSR(-/-) embryos exhibited thymus atrophy owing to a developmental defect of T-lymphoid cells. Clearance of apoptotic cells by macrophages was impaired in both liver and thymus of PSR(-/-) embryos. However, this did not induce up-regulation of inflammatory cytokines. These results indicate that during embryonic development, PSR-mediated apoptotic cell uptake is required for definitive erythropoiesis and T lymphopoiesis, independently of the prevention of inflammatory responses.     

Murine extramedullary erythropoiesis induced by tick infestation

Tick saliva contains molecules that modulate the haemostasis, pain/itch responses, wound healing and immune defences of the host. Using BALB/c mice that were each infested with 10 nymphs of Dermacentor andersoni Stiles (Acari: Ixodidae), an attempt has now been made to determine the influence of tick infestation on the expression of leucocyte adhesion molecules in the host. The ticks became fully engorged by the fourth to sixth day of infestation. On the fourth day of infestation, the results of flow cytometry indicated that 2% of the host's splenocytes were expressing high levels of CD49 (alpha4 integrin of VLA-4) and low levels of CD11a (alphaL subunit of the integrin LFA-1). By the eighth day of infestation, 30% of the hosts' splenocytes had this phenotype and were negative for the lineage markers CD3e (T-lymphocytes), DX5 (natural-killer cells of a BALB/c lineage), B220 (B-lymphocytes), CD11b (monocytes/macrophages, granulocytes, natural-killer cells, activated T-lymphocytes, and B-1 cells) and CD11c (myeloid and splenic dendritic cells). Histological examination of the spleens from infested mice revealed disruption of the white-pulp/red-pulp demarcations and the presence of a large number of basophilic normoblasts. The CD11a(lo) population of splenocytes from the tick-infested mice was positive for TER-119 but negative for CD3, B220, CD11b and Gr, confirming that the splenocytes were members of the erythroid lineage. These results indicate that, within 8 days of their initiation, the tick infestations induced extramedullary erythropoiesis in the spleens of their murine hosts.     

Autonomous erythropoiesis induced by a virus.

In this communication, data are presented on a virus-induced murine polycythemia (FV-P) that might serve as a useful model in providing information toward an understanding of autonomous erythropoiesis. In addition, the virus that induces this autonomous erythropoiesis is defective and requires a leukemia virus to manifest the spleen focus formation and polycythemia. An analysis of the defectiveness of FV-P has not only increased our understanding of the relationship of FV-P and leukemia helpers but has also shown that this defective virus system may be exploited to detect and characterize any virus isolate or component involved in human polycythemia.     

硫酸软骨素对大鼠酒精性肝纤维化模型的影响

目的探讨硫酸软骨素对酒精性肝纤维化的治疗作用。方法用连续灌服酒精的方法建立大鼠酒精性肝纤维化模型,在造模成功后给予硫酸软骨素治疗6周(25mg/Kg,腹腔注射,每日一次)。测定血清和肝脏匀浆丙二醛(MDA)水平,采用VanGieson染色法显示肝脏组织中胶原的表达,免疫组化检测肝组织转化生长因子β1(TGFβ1)、金属蛋白酶组织抑制因子1(TIMP1)的表达。结果硫酸软骨素能减轻酒精性肝纤维化的组织病理改变,降低酒精性肝纤维化大鼠肝组织胶原和TIMP1的表达。酒精性肝纤维化中,肝组织MDA和TGFβ1的表达增加,使用硫酸软骨素可显著抑制MDA和TGFβ1的表达(P<0.01)。结论硫酸软骨素对酒精性肝纤维化有治疗作用,其作用机制可能与影响MDA和TGFβ1的表达水平相关。     

ConA诱发昆明小鼠T细胞依赖性肝脏损害

目的制作ConA引发昆明小鼠T细胞介导的肝损害方法参考Tiegsetal工作的基础上，本文经尾静脉将ConA2mL（10，20，40mg／Kg）注入昆明小鼠（n＝6）体内．8h后测定血清ALT及肝组织MDA，并作肝组织HE染色，病理学检查．对照组（n＝6）仅采用溶剂PBS2mL另外，用环胞素A（CSA）130mg／kg预处理（－15h，－1h），并作同样检查，观察预防效果．结果成功地诱发了T细胞介导的特异性肝脏损害，其肝脏损害为ConA剂量依赖性；肝组织病理示，门管区大量淋巴细胞浸润，并可见点片状肝细胞坏死．以CSA预先抑制T细胞活化，则未见肝脏损害，肝组织病理也未发现淋巴细胞的浸润．结论ConA诱发的肝损害为无种属特异性的T细胞介导的肝损害，他为深入研究病毒性与自身免疫性肝损害的病理机制提供了又一方便理想的实验动物模型．     

Effective erythropoiesis and HbF reactivation induced by kit ligand in beta-thalassemia

In human beta-thalassemia, the imbalance between alpha- and non-alpha-globin chains causes ineffective erythropoiesis, hemolysis, and anemia: this condition is effectively treated by an enhanced level of fetal hemoglobin (HbF). In spite of extensive studies on pharmacologic induction of HbF synthesis, clinical trials based on HbF reactivation in beta-thalassemia produced inconsistent results. Here, we investigated the in vitro response of beta-thalassemic erythroid progenitors to kit ligand (KL) in terms of HbF reactivation, stimulation of effective erythropoiesis, and inhibition of apoptosis. In unilineage erythroid cultures of 20 patients with intermedia or major beta-thalassemia, addition of KL, alone or combined with dexamethasone (Dex), remarkably stimulated cell proliferation (3-4 logs more than control cultures), while decreasing the percentage of apoptotic and dyserythropoietic cells (<5%). More important, in both thalassemic groups, addition of KL or KL plus Dex induced a marked increase of gamma-globin synthesis, thus reaching HbF levels 3-fold higher than in con-trol cultures (eg, from 27% to 75% or 81%, respectively, in beta-thalassemia major). These studies indicate that in beta-thalassemia, KL, alone or combined with Dex, induces an expansion of effective erythropoiesis and the reactivation of gamma-globin genes up to fetal levels and may hence be considered as a potential therapeutic agent for this disease.     

硫酸软骨素对大鼠酒精性脂肪肝模型的影响

目的 观察硫酸软骨素对酒精性脂肪肝的治疗作用。方法 用连续灌服酒精的方法建立大鼠酒精性脂肪肝模型。在造模成功后给予硫酸软骨素治疗4周，观察一般情况及测定血清肝功能指标和血脂参数，并对大鼠肝脏行病理学检查。结果 连续灌服酒精8周后大鼠形成酒精性脂肪肝，给药4周后，硫酸软骨素（25mg/kg）组成显著降低血中丙氨酸氨基转移酶（ALT）和天门冬氨酸氨基转移酶（AST）活性与血中和肝脏中丙二醛（MDA），甘油三酯（TG），总胆固醇（TC）含量，改善肝脏炎症活动度与脂肪性变。结论 硫酸软骨素能改善酒精性脂肪肝大鼠体内脂质代谢，对酒精性脂肪肝具有一定的治疗作用。     

铁调素在CCl_4诱导的小鼠肝纤维化模型中的动态变化

目的研究铁调素(hepcidin)在CCl4诱导的小鼠肝纤维化中的动态变化。方法 C57BL/6小鼠给予CCl4灌胃建立肝纤维化模型,通过HE和Masson染色验证小鼠肝损伤及纤维化程度,并通过普鲁士蓝染色检测在肝纤维化进展过程中肝脏铁沉积情况;通过两步法胶原酶原位灌注与密度梯度离心分离肝脏原代肝细胞、肝星状细胞、Kupffer细胞;通过实时荧光定量PCR检测肝纤维化进展过程中hepcidin和肿瘤坏死因子(TNF)α、白细胞介素(IL)6、IL-1β的表达水平。计量资料两组间比较采用t检验。结果通过对肝组织进行HE和Masson染色发现,肝纤维化程度随造模时间的延长而逐渐加重,停止造模后肝纤维化出现自发性逆转;普鲁士蓝染色提示,随着造模时间的延长,肝脏铁沉积逐渐增加,造模4周时肝脏铁沉积面积较前增加,与正常对照组相比差异有统计学意义(t=4.772,P0.05),但在造模6周时无明显增加,仍高于正常对照,差异有统计学意义(t=10.32,P0.05);停止造模的自发逆转过程中铁沉积又出现下降;通过实时荧光定量PCR检测发现,肝脏中TNFα、IL-1β、IL-6在CCl4诱导的小鼠肝纤维化模型中持续增高,造模6周时达峰值,与正常对照组相比差异有统计学意义(t值分别为4.322、9.707、5.678,P值均0.05);肝脏hepcidin在此纤维化模型中表达早期升高,造模4周时已达峰值,与正常组相比差异有统计学意义(t=2.590,P0.05),但在自发逆转过程中表达降低,峰值早于炎症因子的表达。结论肝脏中铁沉积在CCl4诱导的小鼠肝纤维化进展过程中逐渐增加;hepcidin的表达在肝纤维化进展过程中逐渐升高,与炎症因子的表达相关。     

芦荟大黄素对血吸虫病性肝纤维化小鼠的影响

目的:探讨芦荟大黄素对血吸虫肝纤维化的影响。方法:采用日本血吸虫尾蚴感染小鼠建立血吸虫性肝纤维化模型,用芦荟大黄素0.3mg.kg-1.d-1治疗8周。测定小鼠肝脏匀浆丙二醛(MDA)水平,免疫组化检测其肝组织转化生长因子β1(TGF-β1)、血管内皮生长因子(VEGF)、局部黏着斑激酶(FAK)、Ⅰ型胶原和Ⅲ型胶原的表达。结果:芦荟大黄素能减轻血吸虫性肝纤维化的组织病理改变,使血吸虫肝纤维化小鼠肝脏Ⅰ型胶原和Ⅲ型胶原的表达降低,显著抑制肝组织中TGF-β1、VEGF和FAK的表达(P<0.01)。结论:芦荟大黄素对血吸虫性肝纤维化有治疗作用,其作用机制可能与影响TGF-β1、VEGF和FAK的表达相关。     

Further studies on cyclic erythropoiesis in mice

When young adult female W/Wv mice are given 0.5 micro+Ci 89Sr/g body weight intravenously, their hematocrit values oscillate from nadirs of 26% to zeniths of 42% with a periodicity of 16 days [1]. The response of the W/Wv mouse to an assortment of radioactive and hematologic stresses have been examined in an effort to understand better the pathophysiology of cyclic erythropoiesis. When the dose of 89Sr is increased, the amplitude of cycling increases as nadirs are lowered, but periodicity is unchanged. When the dose of 89Sr is lowered to 0.3 microCi or less, cyclic erythropoiesis of substantial amplitude is observed only after five or six microoscillations. A single hematopoietic insult of 80 rad x-irradiation coupled with phlebotomy produces a transient form of cyclic erythropoiesis, namely, a series of dampened oscillations prior to recovery. Finally, we report that Wv/Wv mice exhibit a form of cyclic erythropoiesis in response to 0.5 microCi 89Sr/g body weight, in which the hematocrit values of successive nadirs gradually increase, and stabilize at about 100 days. 89Sr does not induce cyclic erythropoiesis in the +/+, W/+, or W/v/+ mice, the Hertwig strain of anemic mice, or in normal BDF1 mice.