APP17肽对APP转基因小鼠学习记忆能力和海马神经细胞凋亡的影响

目的观察APP(-βamyloid precursop protein,APP)17肽(APP695中319-335肽段)对APP转基因小鼠(APP695V717I)学习、记忆能力及海马神经细胞凋亡的影响。方法3月龄的APP695转基因小鼠随机分为模型组和APP17肽治疗组,正常对照组采用月龄和性别与之相匹配的C57BL/6J小鼠。APP17肽治疗组给予皮下注射APP17肽,每只每次0.34μg,每周3次;模型组和正常对照组给予等体积NS。应用水迷宫试验观察小鼠学习、记忆功能的变化,以流式细胞技术分析海马神经细胞凋亡率和线粒体膜电位的变化。结果(1)水迷宫试验结果显示,模型组小鼠存在明显学习和记忆功能障碍,其第3、4、5天游完全程的时间[(93.22±16.35)、(86.73±20.26)、(77.13±29.35)s]和错误反应次数[(6.63±2.16)、(5.81±2.13)、(5.33±1.41)次]均较正常对照组[分别为(70.89±20.19)、(61.25±21.88)、(54.63±16.92)s和(5.01±1.93)、(2.97±0.96)、(2.31±1.01)次]增多(P<0.05);APP17肽治疗组小鼠的行为学障碍明显轻于模型组(P<0.05),其上述水迷宫检测结果与正常对照组比较差异无统计学意义。(2)与正常对照组小鼠海马神经细胞凋亡发生率[(3.13±1.19)%]和线粒体膜电位[(176.39±13.88)mV]比较,模型组凋亡发生率[(8.06±2.31)%]显著增加(P<0.01)而线粒体膜电位[(97.51±15.73)mV]明显降低(P<0.01);APP17肽治疗组检测结果与正常对照组接近,海马神经细胞凋亡发生率[(4.38±1.26)%]低于模型组(P<0.01),线粒体膜电位[(168.35±19.29)mV]高于模型组(P<0.01)。结论APP695转基因小鼠存在学习和记忆功能障碍,且其海马神经细胞凋亡率增加,线粒体膜电位降低;APP17肽能够明显改善该转基因小鼠的学习和记忆能力,其作用机制可能是通过稳定线粒体膜电位及抑制凋亡发生而实现。     

异种移植动物模型-转人CD59 cDNA首建小鼠的培育

目的　培育转人CD5 9cDNA首建小鼠 ,以进一步研究异种移植 ,并为建立鼠系奠定基础。方法　构建转基因结构pEGFP -C1-OMT -CD5 9,限制性内切酶切除质粒载体 ,回收、纯化包括人CD5 9cDNA、绿色荧光蛋白(greenfluorescentprotein ,GFP)基因及各自启动子的约 3 .3kb的基因片段 ,用显微注射法将此片段注入小鼠受精卵 ;提取F0 代小鼠尾组织DNA ,用PCR法初选 ,再用Southern杂交法对PCR阳性鼠进一步筛选 ,确定阳性转基因首建小鼠。结果　共注射 5 90枚受精卵 ,移植于 2 4只受体母鼠中 ,出生F0 代小鼠 73只 ;PCR初选有 8只呈阳性(6♂∶2♀ ) ,Southern杂交有 2只呈阳性 (1♂∶1♀ ) ;经粗略估算 ,整合外源基因拷贝数分别为 3和 10。结论　成功地培育出转人CD5 9cDNA首建小鼠 ,用PCR和Southern杂交法证实了外源片段的整合     

Learning and sexual deficiencies in transgenic mice carrying a chimeric vasoactive intestinal peptide gene

The molecular mechanisms responsible for behavior are largely unknown. A state of the art model, paving the path from genes to behavior, is offered by transgenic animals. Candidate molecules are classic neuropeptides, such as vasoactive intestinal peptide (VIP). Transgenic mice harboring a chimeric VIP gene driven by the polyoma promoter were produced. Behavioral studies revealed learning impairment and prolonged retardation in memory acquisition in the genetically altered animals. Furthermore, reduced performance was observed when the male transgenic mice were tested for sexual activity in the presence of receptive females. Surprisingly, radioimmunoassays showed an approx 20% decrease in the VIP content of the transgenic mice brains. To directly assess genetically reduced VIP content as a cause for learning impairment, transgenic mice carrying diphtheria toxia-encoding sequences driven by the rat VIP promoter were created. These animals had reduced brain VIP and exhibited deficiencies in learning abilities, strongly supporting an important neurobiological function for VIP in vivo.     

The human desmin gene: A specific regulatory programme in skeletal muscle both in vitro and in transgenic mice

Desmin synthesis is restricted to cardiac, skeletal and smooth muscles. In several familial myopathies involving fibre disorganization, filamentous aggregation of desmin has been characterized. During the development of the mouse embryo, desmin is one of the first muscle proteins detected in both the heart and the somites. To identify the DNA sequences involved in the regulation of desmin gene expression a 4.5 kb 5′-flanking region of the human desmin gene has been isolated. Different mutants were used to characterize specific enhancers in vitro and in vivo. The results obtained with transgenic mice provide evidence that the 1 kb cis-regulatory sequences, functional in skeletal muscle cells in vitro, confer specific developmental control for skeletal muscles. Furthermore, distinct programmes for cardiac and skeletal muscle-specific expression of the desmin gene are revealed.     

乙型肝炎病毒转基因小鼠C57-TgN(adr2.0)SMMU品系的免疫病理研究

目的: 研究乙型肝炎病毒 (HBV)转基因小鼠C57 TgN(adr2. 0型)SMMU品系的免疫病理学特征, 并与临床人慢性乙肝相比较。方法: 以 20只SPF级肝脏有明显病变的HBV转基因小鼠为研究对象, 用间接免疫荧光法通过流式细胞仪, 分别检测转基因小鼠及正常C57BL/6小鼠外周血淋巴细胞表面CD3、CD4和CD8表达的水平, 同时取其肝组织和5例本院病理科存档确诊为慢性中度乙型肝炎患者的肝组织石蜡标本, 用EnVision免疫组化染色法检查肝组织内T细胞亚群的分布。结果: 转基因小鼠外周血淋巴细胞表面CD3、CD4和CD8表达的水平低于正常对照组小鼠; 肝组织内浸润的单个核细胞多数为CD3 CD4 细胞, 未发现CD57 、CD8 细胞。慢性乙型肝炎患者的肝组织内浸润的单个核细胞主要为CD3 CD4 或CD3 CD8 细胞和少量CD57 细胞。结论: C57 TgN(adr2. 0型 )SMMU的HBV转基因小鼠外周血及肝组织中CD的表达与人慢性乙肝患者的外周血及肝组织有明显不同。     

Increased Hepatic Cholesterol Accumulation in Transgenic Mice Overexpressing Human Secretory Phospholipase A2 Group IIA

It has been demonstrated in transgenic mice that the overexpression of human phospholipase A2 group IIA (sPLA2), an acute-phase reactant, is associated with depressed plasma cholesterol levels, altered lipoprotein compositions, and increased lipid depositions in aortic walls. It was the aim of the present study to investigate whether the reduced plasma cholesterol levels in sPLA2-transgenic mice may be due to an increased transfer of lipids from sPLA2-modified lipoproteins to the liver and/or other nonvascular tissues. Ten sPLA2-transgenic mice and an equal number of nontransgenic littermates were fed a cholesterol-enriched (1%) diet for 13 weeks. After autopsy, cholesterol and triglyceride concentrations were measured in homogenates of liver, spleen, kidney, and myocardial tissues. Compared to the nontransgenic controls, the sPLA2-transgenic mice exhibited significantly lower plasma cholesterol levels, which was due to a reduction in both HDL and beta-lipoprotein (LDL + beta-VLDL) cholesterol. Liver tissues from the transgenic mice were found to contain significantly increased concentrations of free and esterified cholesterol, which was not associated with increased triglyceride concentrations. Spleen, kidney, and heart tissues of the two animal groups showed no significant differences in cholesterol or triglyceride concentrations. The findings suggest that the overexpression of human secretory phospholipase A2 group IIA leads to an enhanced delivery of cholesterol from phospholipolysed lipoproteins to the liver. This mechanism is likely to contribute to the development of hypocholesterolemia observed in patients with inflammatory diseases.     

免疫磁珠法分离白血病转基因小鼠骨髓造血干细胞

本文分离转基因小鼠骨髓造血干细胞。运用针对小鼠干细胞表面特异表达的干细胞抗原 1(stemcellantigen 1,Sca 1)的单克隆抗体和包被于磁颗粒表面的第二抗体 ,采用磁吸附细胞分选方法 (MACS )分离小鼠骨髓造血干细胞 ,用流式细胞术 (FACS )检测MACS分离后骨髓细胞中干细胞 (Sca 1阳性细胞 )比例 ,监测细胞分选效果。结果显示MACS分离后骨髓细胞中Sca 1阳性细胞所占比例达 85 %以上 ,涂片观察发现细胞组成和细胞形态学特征与FACS所得结果一致。MACS可以从转基因小鼠全骨髓细胞中分离出Sca 1阳性的骨髓造血干细胞 ,细胞纯度可达 85 %以上。     

Altered splenic B cell subset development in mice lacking phosphoinositide 3-kinase p85alpha

The signaling enzyme phosphoinositide 3-kinase (PI3K) is activated following B cell receptor (BCR) engagement and by many other receptors on B lymphocytes. Mice lacking p85alpha, the predominant PI3K regulatory isoform, exhibit defects in B cell development and activation that are grossly similar to those found in mice lacking Bruton's tyrosine kinase (Btk) and other critical signaling molecules. However, a detailed analysis of splenic B cell subsets in p85alpha-deficient mice has not been reported. Here we show that these mice are deficient in four major B cell subsets: transitional-1, transitional-2, follicular and marginal zone. These defects are distinct from those observed in Xid mice that express a mutant Btk unable to interact with PI3K lipid products. Moreover, mice with both genetic lesions exhibit even greater impairment in B cell development. Finally, we show that transgenic expression of the anti-apoptotic protein Bcl-2 in p85alpha-deficient mice restores the transitional B cell subsets but not the marginal zone subset, and produces a follicular population with an aberrant phenotype. These findings establish a role for PI3K-p85alpha in differentiation of both follicular and marginal zone B cells, and suggest that these functions are required not solely for the propagation of anti-apoptotic signals.