以致癌物诱导小鼠皮肤产生活性黑色素细胞:一种检测皮肤致癌物的新方法

迄今已有不少观察,证明化学致癌物可诱导皮肤黑色素母细胞(melanoblasts)的黑色素形成(melanogenesis)。因此,提出黑色素细胞激活作用(melanocyte activation)可用作为检测化学致癌物的方法之一。为进一步对这种测试系统作出评价,本研究应用多种强致癌物,弱致癌物,肿瘤促进剂,以及非致癌物质对有色素成年小鼠内毛囊表皮(interfollicular epidermis)黑色素细胞的作用。     

维生素A缺乏对小鼠胚胎Hox基因表达的影响

目的：观察维生素Ａ（ＶＡ）缺乏对小鼠胚胎ＨｏｘＣ４（３．５）和ＨｏｘＤ１０（４．５）基因表达量的影响。方法：初断乳的昆明小鼠,雌鼠４０ 只均分为正常对照组（Ａ）和维生素Ａ缺乏组（Ｂ）,分别饲含ＶＡ４０００ ＩＵ／ｋｇ 饲料和ＶＡ ０ ＩＵ／ｋｇ 饲料。雄鼠饲以普通饲料。在饲养的第１７ 周按雌∶雄＝ ２∶１ 合笼交配。在怀孕的第１２ 天和第１４ 天,分别对孕鼠颈椎脱臼处死,立刻剖腹取出胎鼠,迅速置于液氮中速冻后置于－ ７０℃冰箱保存。用地高辛标记的探针,采用原位杂交方法探测小鼠胎儿ＨｏｘＣ４（３．５）和ＨｏｘＤ１０（４．５）基因ｍ ＲＮＡ含量。结果：ＶＡ缺乏时,ｍ ＲＮＡ的含量明显减少。结论：ＶＡ缺乏导致Ｈｏｘ 基因表达量下降,从而影响小鼠胚胎的正常发育。     

白血病小鼠模型的建立及应用

小鼠是白血病深入研究重要的动物模型,本文主要综述白血病小鼠模型的应用.     

一种褪黑素片的小鼠致突变性研究

[目的]研究一种褪黑素片对小鼠是否有致突变作用。[方法]以10.0、5.0和2.5 g/kg.BW 3个剂量的褪黑素片蒸馏水溶液给小鼠灌胃,另设阴性对照组(给予蒸馏水)及阳性对照组(40 mg/kg.BW的环磷酰胺),按GB15193.5-2003进行小鼠骨髓微核试验,按GB 15193.7-2003进行小鼠精子畸形试验。[结果]各剂量组微核率及精子畸形率与阴性对照组比较差异无显著性;阳性对照组微核率及精子畸形率与阴性对照组比较差异有显著性。[结论]在本研究剂量范围内该褪黑素片对小鼠未见致突变性。     

VSMC-Cx43-/-条件性基因敲除小鼠模型的构建及基因型鉴定

目的 应用CRISPR-Cas9技术和LoxP-Cre系统构建血管平滑肌缝隙连接蛋白Cx43条件性基因敲除小鼠(VSMC-Cx43-/-)模型.方法 采用受精卵同源重组的方式,对Gja1基因进行flox修饰.通过体外转录的方式,获得Cas9 mRNA和gRNA;通过In-Fusion cloning的方法构建同源重组载...     

羟基脲诱导神经管畸形小鼠模型及与其他小鼠模型的比较研究

目的 本研究拟通过干扰新的叶酸相关代谢-核苷三磷酸还原成相应的脱氧核苷三磷酸通路中的关键酶-核苷酸还原酶,诱导构建神经管畸形(NTDs)小鼠模型,并且与前期构建的NTDs小鼠模型进行比较.方法 实验小鼠选用C57BL/6J小鼠,购自北京华阜康公司,雌鼠60只,雄鼠30只,小鼠年龄7～8周,体重18～20 g,常规饲养于...     

VSMC-Cx43-/-条件性基因敲除小鼠模型的构建及基因型鉴定

目的应用CRISPR-Cas9技术和LoxP-Cre系统构建血管平滑肌缝隙连接蛋白Cx43条件性基因敲除小鼠(VSMC-Cx43^-/-)模型。方法采用受精卵同源重组的方式,对Gja1基因进行flox修饰。通过体外转录的方式,获得Cas9 mRNA和gRNA;通过In-Fusion cloning的方法构建同源重组载体,该载体包含3.0 kb 5’同源臂、1.9 kb的flox区域和3.0 kb 3’同源臂。将Cas9 mRNA、gRNA和donor vector显微注射到C57BL/6J小鼠的受精卵中,获得F0代小鼠。PCR扩增及测序鉴定阳性的F0代小鼠与C57BL/6J小鼠交配获得3只阳性F1代小鼠(Cx43^flox/+)。将获得的flox杂合子Cx43^flox/+小鼠自交,获得flox纯合子Cx43^flox/flox小鼠。然后用Cx43^flox/flox小鼠和Myh11-CreERT2小鼠交配,最终获得flox纯合且Cre阳性的实验组小鼠(该小鼠简写为:VSMC-Cx43^-/-)和flox纯合且Cre阴性的对照组小鼠(Cx43^flox/flox)。用PCR进行基因型鉴定,用Western blot技术检测Cx43在大脑中动脉、冠脉、肺动脉和肾动脉组织中的表达,以明确基因敲除小鼠是否构建成功。结果基因型鉴定、免疫荧光和Western blot检测结果表明VSMC-Cx43^-/-基因敲除小鼠模型构建成功,小鼠一般性状无改变,小鼠大脑中动脉、冠脉、肺动脉和肾动脉组织中Cx43蛋白表达均下降。因此,可作为长期稳定模型研究血管平滑肌Cx43的功能。结论应用CRISPR-Cas9技术和LoxP-Cre系统成功构建了VSMC-Cx43^-/-基因敲除小鼠模型,为深入研究Cx43在血管疾病中的作用提供工具。     

锌缺乏及补锌对小鼠胚胎HOX3.5基因表达的影响

为研究锌缺乏及补锌对小鼠胚胎HOX3 5基因表达的影响 ,将昆明种雌性小鼠随机分为缺锌组(ZD)、缺锌后补锌组 (ZR)和常锌对照组 (ZN)。ZD组及ZR组喂饲含锌量为 (3 0± 0 5 )mg kg的缺锌饲料 ,但ZR组小鼠从孕第 7天开始改喂含锌量为 30mg kg的常锌饲料。ZN组小鼠一直食用常锌饲料。经 2 5天喂养后 ,与同系成年雄鼠交配。于妊娠第 12天时处死动物 ,并立刻剖腹取出胎鼠。用地高辛标记的探针 ,采用原位杂交方法检测小鼠胚胎HOXC4(3 5 )基因mRNA在鼠胚冰冻切片上的表达量。结果发现 :ZD、ZR组HOX3 5基因阳性表达的面密度及其平均光密度明显低于ZN组 (P <0 0 5 )。提示 :锌缺乏时可导致HOX3 5基因表达量下降 ,这种调控作用乃发生在胚胎发育的早期 ,从孕早期 (孕 7天 )开始补锌仍无法纠正     

铝对小鼠认知能力及β-APP基因表达的影响

[目的]探讨铝暴露对小鼠认知功能及脑组织β-淀粉样前体蛋白（β-APP）基因表达的影响。[方法]动物模型高、中、低剂量组每日用AlCl3含量分别是120、12、1.2mg/kg的饲料进行喂养,对照组每日正常饲养。染毒3个月后用跳台试验、避暗试验和水迷宫试验检测小鼠的认知功能。小鼠脑组织中β-APP mRNA的表达用逆转录-聚合酶链反应（RT-PCR）法检测。[结果]与对照组相比,高、中剂量组跳台试验潜伏期明显缩短（P〈0.05）,错误次数增多（P〈0.05）;避暗试验高剂量组潜伏期较对照组明显缩短（P〈0.05）,错误次数明显增多（P〈0.05）;水迷宫试验低、中、高剂量组随着染铝浓度的增加潜伏期明显延长（P〈0.05）,高、中剂量组穿越平台的次数与对照组相比明显减少（P〈0.05）。高、中剂量组β-APP mRNA的表达量明显增高（P〈0.05）。铝暴露剂量与跳台试验潜伏期（rs=-0.725,P〈0.05）、避暗试验潜伏期（rs=-0.765,P〈0.01）、Morris水迷宫试验潜伏期（rs=0.097,P〈0.05）、跳台试验错误次数（rs=0.565,P〈0.01）、避暗试验错误次数（rs=0.509,P〈0.05）之间均存在剂量-效应关系。铝暴露与β-APP mRNA的表达量呈明显的正相关（rs=0.743,P〈0.05）。[结论]铝暴露可导致小鼠认知功能障碍及β-APP的过度表达,这可能是铝致小鼠认知功能障碍的重要机制之一。     

Cramp基因对小鼠脾脏及胸腺细胞发育的影响

目的研究Cramp基因敲除在衰老过程中对小鼠脾脏及胸腺细胞发育及组成的影响。方法应用流式细胞仪分析不同年龄Cramp基因敲除C57BL/6J小鼠及同龄野生型小鼠的脾脏、胸腺等组织器官中各种细胞的比例。结果与野生型小鼠相比,Cramp基因敲除小鼠的脾脏、胸腺等组织器官中各种细胞的比例均无明显变化。结论本研究中,Cramp基因敲除对不同年龄小鼠脾脏及胸腺等组织器官的细胞发育无明显影响。     

Prevnar-13 vaccine failure in a mouse model for vitamin A deficiency

Streptococcus pneumoniae (pneumococcus) is responsible for serious pediatric respiratory infections, and kills close to one million children under the age of five each year. Unfortunately, the Prevnar-13 vaccine (PCV-13) that is used to protect children from the serious consequences of pneumococcus infections is not always successful. Given that vitamin A deficiency (VAD) is known to affect children in both developed and developing countries, we asked if VAD could be responsible, at least in part, for PCV-13 vaccine failures. In a mouse model for VAD, we found that PCV-13 failed to elicit binding and neutralizing antibody activities. Unlike vaccinated, vitamin-replete animals, vaccinated VAD animals were not protected from lethal pneumococcus infections. Results suggest that children with VAD may be susceptible to serious pneumococcal infections even after having received the PCV-13 vaccine.     

p53 phosphorylation in mouse skin and in vitro human skin model by high-dose-radiation exposure

The skin is an external organ that is most frequently exposed to radiation. High-dose radiation initiates and promotes acute radiation injury. Thus, it is important to investigate the influence of high-dose radiation exposure on the skin at the molecular level. The post-translational modification of p53 plays a central role in radiation responses, including apoptosis and cell growth arrest. Although it is well known that ataxia telangiectasia mutated (ATM) kinase and DNA-dependent protein kinase (DNA-PK) can phosphorylate Ser15/Ser18 of p53 in vitro, the post-translational modification pattern and the modifier of p53 in the skin after exposure to high-dose X-rays are not yet well understood. Here we show that the phosphorylation of p53 on Ser15/Ser18, as well as the phosphorylation of histone H2AX on Ser139, was detected in the keratinocytes of the mouse skin and human skin models after high-dose X-ray irradiation. Following high-dose X-ray irradiation, both proteins were also phosphorylated in the skin keratinocytes of both ATM gene knockout mice and DNA-PK-deficient SCID mice.     

A novel mouse model for immunogenic evaluation of human HBV vaccines

To prepare a human HBV vaccine, investigators need an animal model that can help them screen and prioritize vaccine candidates. In this study, HBV/HLA-A2.1 double transgenic mice (dTg), confirmed by analysis of genomic integration and by observation of long-term expression of HBV and HLA genes, were generated for the first time. The HBV/HLA-A2.1 dTg not only display tolerance to HBV antigens (Ags), but also have the ability to process and present HLA-A2 restricted antigenic epitopes. The animals vaccinated with HLA-A2 restricted HBc_18–27 or HBs_183–191 epitope peptide vaccine induced effective HLA-A2 restricted peptide-specific cytolytic T lymphocyte responses. This was supported by the evidence of cytotoxicity assay, ELISPOT and tetramer staining analysis. Furthermore, T cell tolerance against HBV Ags in HBV/HLA-A2.1 dTg was broken by the HBc_18–27 or HBs_183–191 peptide vaccine. In conclusion, HBV/HLA-A2.1 dTg was demonstrated to be useful model for in vivo immunogenicity testing of human HBV-based vaccines.     

The interaction of vitamin A deficiency and rotavirus infection in the mouse

Weanling mice were fed on a control diet ad lib., a vitamin A-deficient diet ad lib. or pair-fed to the intake of the vitamin A-deficient group. Vitamin A deficiency was induced by 63-70 d of age. On day 77 mice were given 30 microliters rotavirus/mouse orally and examined histologically 1 week later. There were no changes in relative liver weight in any of the groups, but following infection animals deficient in vitamin A showed a significant increase in spleen weight compared with the other groups. The relative weight of the thymus was reduced by vitamin A deficiency, in both non-infected and infected animals. The histology of the spleen, thymus and small intestine was similar in all three dietary groups before infection. The number of goblet cells per duodenal villus in vitamin A-deficient animals was significantly lower than that of control and pair-fed animals. In the small intestine of vitamin A-deficient animals, rotavirus infection caused dramatic changes to the mucosa, with almost complete destruction of the tips of the villi, but control and pair-fed animals had normal villi. It is concluded that although rotavirus infection and vitamin A-deficiency cause few changes alone, in their action together there is significant destruction of the mucosal barrier of the small intestine.     

Dietary copper deficiency and autoimmunity in the NZB mouse

NZB mice were exposed from birth to a diet either adequate or deficient in copper. By age 6 wk the mice exposed to the copper-deficient diet showed symptoms characteristic of copper deficiency (anemia, hypoceruloplasminemia, and achromatrichia). The splenic lymphocytes from the copper-deficient group had reduced numbers of cells expressing the following surface markers: Ly-5, Ly-1, B-220, and sIg. Less than 10% of the splenic lymphocytes in this group were cycling, as determined by flow cytometry analysis. The spontaneous 96-h anti-ss-DNA levels in the copper-deficient group were lower than those in the control group. The exogenous colony-forming units (CFUs) were significantly enhanced in the copper-deficient mice. The decreased splenic lymphoid populations, decreased anti-ss-DNA titers, and increased exogenous CFUs in the copper-deficient mice appear to be due to an increase in erythropoiesis at the expense of lymphopoiesis.     

一种简捷可靠的小鼠气管插管新方法

目的探索一种安全、高效的小鼠气管插管新方法。方法这种新方法是在小鼠颈前作一小切口,显露气管后,经口腔作气管内插管,费时仅约1 m in。结果经过1300多次实验,无一例失败,成功率达100%。结论这种简捷实用、安全可靠的小鼠气管插管新方法无需特殊设备及体位,一人操作即能完成,可显著提高以小鼠为实验动物模型的成功率。