慢性复合式应激对C57BL/6J小鼠凝血功能的影响

目的探讨慢性应激对C57BL/6J小鼠凝血功能的影响。方法将20～25g雄性C57BL/6J小鼠分成应激组及相应的对照组。应激组小鼠独笼饲养,将6个日相和6个夜相刺激及一个全天刺激随机安排到1w内,每w刺激顺序随机重新组合,连续8w。对照组动物则每5～6只小鼠合笼饲养,自由给水,整个实验过程中不接受任何刺激。两组动物均于刺激后的1、2、4、8w经内眦取血,用于空腹血糖含量,3、5、8w取血用于纤维蛋白原及凝血因子的检测。结果①与对照组相比较,应急组小鼠各时间点血糖含量均明显高于对照组(P0.01)。②纤维蛋白原含量检测显示,刺激后的3、5、8w应激组小鼠均低于对照组(P0.01);而出、凝血时间检测结果显示,刺激后各时间点应激组小鼠与对照组无显著差异。结论复合式慢性应激刺激可成功引起C57BL/6J小鼠处于应激状态,对C57BL/6J小鼠凝血功能造成一定的影响。     

C57BL/6J小鼠慢性应激形成过程中血细胞变化特点

目的 观察C57BL/6J小鼠慢性应激形成过程中血细胞的变化特点.方法 将20～25 g雄性C57BL/6J小鼠分成应激组及对照组.应激组小鼠独笼饲养,将6个日相和6个夜相刺激及一个全天刺激随机安排到1 w内,每周刺激顺序随机重新组合,连续8 w.对照组动物每5～6只小鼠合笼饲养,自由给水,整个实验过程中不接受任何刺激.两组动物均于刺激后的1、2、4、8 w经内眦取血,用于空腹皮质醇含量、血细胞计数及白细胞分类的检测.结果 与对照组相比较,应激组小鼠各时间点血浆皮质醇含量均明显高于对照组(P<0.01).刺激后的2、4、8 w应激组小鼠红细胞及血红蛋白含量均低于对照组(P<0.05或P<0.01),刺激后4和8 w应激组小鼠白细胞均低于对照组(P<0.01);而血小板计数和白细胞分类刺激后各时间点应激组与对照组无显著差异.结论 复合式慢性应激刺激可成功引起C57BL/6J小鼠处于应激状态,对C57BL/6J小鼠血细胞生成造成一定的影响.     

异氟烷对FVB/N小鼠和C57BL/6小鼠超声心动图参数的影响

目的评价异氟烷对FVB/N小鼠和C57BL/6小鼠超声心动图参数的影响。方法使用Visual Sonics Vevo770高分辨率小动物超声仪测量雄性FVB/N小鼠和C57BL/6小鼠超声心动图参数,比较异氟烷对两种品系小鼠心功能及心脏结构的影响。结果 FVB/N小鼠在1%和2%异氟烷麻醉下,心脏收缩功能和心脏结构指标均正常,但FVB/N小鼠在1%异氟烷麻醉下容易觉醒,不易获取清晰稳定的图像;C57BL/6小鼠在1%异氟烷麻醉下能够维持良好的收缩功能,但在2%异氟烷麻醉下,C57BL/6小鼠的收缩功能明显被抑制。结论 2%异氟烷麻醉适用于FVB/N小鼠,1%异氟烷麻醉适用于C57BL/6小鼠。     

链脲菌素剂量对C57BL/6J小鼠糖尿病诱导效应的影响

目的 观察不同剂量链脲菌素(STZ)对C57BL/6J小鼠糖尿病诱导效应的影响,探讨其量效关系及最佳剂量范围.方法 将C57BL/6J小鼠按数字随机法分为9个STZ剂量组(A～I组,STZ分别为30、60、80、100、120、150、180、210、240 ms/kg体重),每组15只,腹腔注射;1个对照组,10只,腹腔注射等体积缓冲液.观察各组血糖、体重、血胰岛素和45 d生存率的变化,分析其与STZ剂量的关系.同时取A、C、G及对照组小鼠胰腺、肾脏组织做病理学检杏,并行免疫组化观察胰腺胰岛素及肾脏CD<,68>的表达.结果 C～G组较对照组血糖增高、体重及血胰岛素含量较对照组下降非常显著(P<0.05),且STZ剂量与血糖呈正相关(r=0.984,P<0.05),与血胰岛素含量呈负相关(r=-0.994,P<0.05).C～G组成模率达86.7%～100%,显著高于A、B组的0和40%(P<0.05);45 d生存率为46.7%～73.3%,显著高于H、I组的13.3%和0(P<0.05).A组胰腺、肾脏组织未见明显破坏;C组及G组出现典型的胰岛萎缩变形,胰岛素分泌颗粒减少,肾小球系膜外基质沉着及球周臣噬细胞浸润.结论 C57BL/6J小鼠腹腔注射STZ以80～180 mg/kg体重的剂量制模率高、生存率高,且靶器官损伤典型;该剂量与血糖呈正相关,与血胰岛素含量呈负相关.     

AMPK基因在C57BL／6J小鼠糖脂代谢中的作用

目的研究腺苷酸活化蛋白激酶（AMPK）基因在C57BL／6J小鼠糖脂代谢中的作用。方法分别取5周龄AMPK基因敲除（AMPK-KO）小鼠和C57BL／6J对照小鼠各24只,分为正常饲料（ND）喂养和高脂高糖饲料（HFD）喂养两组。喂养12周,每两周测定小鼠禁食4h血糖（FBG）,实验结束前行口服糖耐量实验（OGTT）,解剖取样,检测血生化指标、脂酶活性及相关蛋白的表达。结果AMPK-KO小鼠血糖、TC、LDL-C、HbA1c、6-磷酸葡萄糖脱氢酶（G6PD）活性、糖原合成酶激酶（GSK）活性、肝脏PPAR7蛋白表达量明显高于对照小鼠（P〈0．05）;其胰岛素含量、肝糖原含量、肌糖原含量、肝脂酶（HL）活性、脂蛋白酯酶（LPL）活性、总脂酶活性、葡萄糖激酶（GK）活性、肝组织P-AMPK蛋白、葡萄糖转运蛋白4（GluT-4）蛋白的表达量低于对照组（P〈0．05）。结论AMPK基因通过调节C57BL／6J小鼠糖脂代谢,在T2DM的发病中起重要作用。     

布比卡因对Balb/c和C57BL/6小鼠胃酸分泌功能的影响

目的 探讨布比卡因对Balb／c:和C57BL／6小鼠胃酸分泌功能的影响。方法 应用幽门结扎术测定了基础状态下和布比卡因局部镇痛后3小时Balb／c和C57BL／6小鼠的胃酸量(ml),胃酸度(mEq／L)和总酸量(μEq／3h),并将基础状态下两种小鼠和各自应用布比卡因前后的胃酸分泌指标进行比较。结果　基础状态下Balb／c小鼠(n=9)的胃酸量和总胃酸量显著高于C57BL／6小鼠(n=10)的胃酸量和总胃酸量(分别为2.319±0.181和0.825±0.062,P<0.001;29.105±4.90和8.565±1.203,P<0.001);Balb／c小鼠的胃酸度稍高于C57BL／6小鼠(分别为12.311±1.737和10.36±1.313,P=0.37),但无统计学差异。应用布比卡因局部麻醉后Balb／e小鼠(n=6)的胃酸量和总胃酸量显著低于基础状态下的分泌量(分别为2.319±0.181和1.529±0.142,P<0.05:29.105±4.90和11.956±2.516,P<0.05);应用布比卡因局部麻醉后Balb／c小鼠的胃酸度低于其基础状态下的胃酸度(分别为12.311±1.737和6.433±1.189,P=0.07)。应用布比卡因局部麻醉后C57BL6小鼠(n=6)胃酸量、酸度和总胃酸量和基础状态下的分泌量无显著差异(分别为0.825±0.062和0.863±0.105,P=0.84;8.565±1.203和8.725±1.102,P:0.95;10.36±1.313和12.433±1.27,P=0.46)。结论 基础状态下Balb／e利C57BL／     

旋毛虫抗C57BL/6小鼠体内Hepa1-6肝癌细胞作用的研究

目的观察旋毛虫对C57BL/6小鼠体内Hepa1-6肝癌细胞生长的抑制作用。方法将C57BL/6小鼠随机分成8组,每组10只。第1和5、2和6、3和7组分别感染未处理旋毛虫、^60Co处理和紫外线处理旋毛虫,4和8组为不感染旋毛虫对照组,1～4组和5～8组分别于接种旋毛虫前7 d和接种后11 d接种Hepa1-6肝癌细胞。荷瘤后25 d后处死小鼠,测量肿瘤体积、重量及脾脏CD3^＋、CD4^＋、CD8^＋淋巴细胞数量。结果未处理旋毛虫组、^60Co处理组和紫外线处理组小鼠肿瘤体积和重量均显著低于对照组（P〈0.05）;脾脏CD3^＋、CD4^＋百分率和CD4^＋/CD8^＋、CD4^＋/CD3^＋的比值显著高于对照组（P〈0.01或P〈0.05）。结论未处理的旋毛虫、经^60Co和紫外线处理的旋毛虫对C57BL/6小鼠体的Hepa1-6肝癌细胞的生长均有抑制作用,未处理旋毛虫的抑瘤效果最好。     

垂盆草水煎液对不同小鼠急性肝损伤模型的疗效作用

目的复制四氯化碳(CCl4)、D-氨基半乳糖胺联合内毒素(D-Gal N/LPS)、D-氨基半乳糖胺联合肿瘤坏死因子-α(D-Gal N/TNF-α)及刀豆蛋白A(Con A)诱导小鼠急性肝损伤模型,筛选针对垂盆草(Sedum Sarmentosum,SS)水煎液有效的急性肝损伤小鼠模型。方法采用152只雄性6~8周龄C57BL/6小鼠,其中80只小鼠随机分为CCl4+H2O组、CCl4+SS组、D-Gal N/LPS+H2O组、D-Gal N/LPS+SS组、D-Gal N/TNF-α+H2O组、D-Gal N/TNF-α+SS组、Con A+H2O组及Con A+SS组共8组,每组10只,观察各组生存率。其余72只小鼠随机分为Normal组、CCl4+H2O肝功能组、CCl4+SS肝功能组、D-Gal N/LPS+H2O肝功能组、D-Gal N/LPS+SS肝功能组、D-Gal N/TNF-α+H2O肝功能组、D-Gal N/TNF-α+SS肝功能组、Con A+H2O肝功能组及Con A+SS肝功能组共9组,每组8只,检测血浆ALT、AST和乳酸脱氢酶(LDH)水平。结果垂盆草水煎液将CCl4小鼠急性肝损伤模型的生存率由55%提高到90%(P=0.0128)。造模24小时后,CCl4+SS组ALT为(5500.00±426.20)U/L,AST为(4383.00±358.00)U/L,LDH为(6764.00±691.30)U/L,分别低于CCl4+H2O组ALT[(10521.00±1374.00)U/L]、AST[(7328.00±947.80)U/L]、LDH[(13589.00±1542.00)U/L],差异均有统计学意义(P均0.05)。结论垂盆草水煎液对CCl4诱导小鼠急性肝损伤模型有保护作用。     

动脉粥样硬化敏感小鼠C_（57）BL／6J腹膜巨噬细胞源性泡沫细胞模型的建立

泡沫细胞的出现是动脉粥样硬化斑块中有特征性的病理形态改变。本实验选择对动脉粥样硬化形成较敏感的纯系小鼠Ｃ５７ＢＬ／６Ｊ，取其腹膜巨噬细胞与１０ｍｇ·Ｌ－１氧化低密度脂蛋白共同孵育９６ｈ，建立了典型的巨噬细胞源性泡沫细胞模型。实验结果显示，培养的泡沫样细胞与在无脂蛋白培养基中培养的Ｃ５７ＢＬ／６Ｊ小鼠巨噬细胞和在氧化低密度脂蛋白中培养的昆明种小鼠巨噬细胞比较，脂质成分大量增多，出现脂质颗粒，细胞内总胆固醇增加，其中胆固醇酯含量大于游离胆固醇，符合泡沫细胞的定义。本实验从离休细胞培养方面探寻建立小鼠巨噬细胞源性泡沫细胞的可能性，为动脉粥样硬化的形成机理分析和防治研究提供了一种可靠的病理细胞模型。     

长期高脂饮食对C57BL/6小鼠骨骼肌基因表达谱的影响

目的 运用基因芯片技术研究长期高脂饮食对C57BL/6小鼠骨骼肌基因表达谱的影响,探究长期高脂饮食导致小鼠肥胖、胰岛素抵抗(IR)和2型糖尿病(T2DM)的分子机制.方法 20只雄性4周龄C57 BL/6小鼠随机分为正常饮食组和高脂饮食组,各10只,分别饲以基础和高脂饲料.16周后,称量各组小鼠体重;测定血糖、空腹血清胰岛素(FINs)、高密度脂蛋白(HDL)、甘油三酯(TG)、总胆固醇(TC)和游离脂肪酸(FFAs)水平;随后,每组随机选取4只小鼠处死,分离股四头肌,提取总RNA进行基因芯片分析.结果 高脂饮食组与正常饮食组相比,体重显著增加;FINs水平显著升高;HDL水平无显著性差异,而TC、TG和FFA水平均显著升高.采用基因芯片相关统计软件分析数据,结果发现正常饮食组与高脂饮食组相比,骨骼肌共出现590个差异表达基因.其中表达上调基因有321个,表达下调基因有269个.结论长期高脂饮食可以引起C57BL/6小鼠骨骼肌基因谱发生显著变化.     

ZFP580基因在高脂血症小鼠主动脉组织中的表达

目的探讨ZFP580基因在高脂血症小鼠主动脉组织中的表达情况。方法将40只C57BL/6小鼠随机分为正常对照组和高脂血症组。采用逆转录PCR方法,检测2组小鼠主动脉组织中ZFP580的表达。结果 ZFP580在两组小鼠的主动脉组织中均有表达,而高脂血症组表达量明显低于对照组(P0.01)。结论血脂升高使ZFP580在C57BL/6小鼠主动脉组织中表达明显下调,表明ZFP580表达改变与高脂血症的发生存在一定关系。     

缺氧对C57BL/6J小鼠瘦素及其受体基因表达的影响

目的　研究缺氧对小鼠瘦素及其受体 (包括转运性受体Ra、Rc和功能性受体Rb)mRNA表达变化的影响,以进一步明确瘦素和呼吸功能的关系。方法　利用医学自动测控缺氧仓(XQ Ⅰ型)复制机体常压缺氧状态,将小鼠分为正常对照组、缺氧 24h组、缺氧 48h组,然后利用逆转录 聚合酶链反应(RT-PCR)分别定量检测瘦素及其受体mRNA表达水平。根据cDNA条带的灰度值计算其相对含量,各种产物与磷酸甘油醛脱氢酶 (GADPH)的比值表示其相对表达水平。结果(1)缺氧 24h组和缺氧 48h组瘦素mRNA表达水平分别为 0.903±0.190、0.856±0.336,显著高于正常对照组(0.508±0.207,P均<0.05); (2)缺氧 24h组和缺氧 48h组RamRNA表达水平分别为0 724、0.700,分别为正常对照组 (0 630)的 115%、111%; (3)缺氧 24h组和缺氧 48h组RbmRNA表达水平分别为 0.381±0.038、0.345±0.042,与正常对照组(0.258±0.049)比较差异均有统计学意义(P均<0.05); (4)缺氧 24h组和缺氧 48h组RcmRNA表达水平分别为 0.299、0.292,分别为正常对照组(0.133)表达水平的 224%、219%。结论　缺氧作为一种独立因素可在一定范围内刺激机体瘦素、瘦素受体Ra、Rb、Rc基因表达增加,从而在正向调节机体呼吸功能中发挥重要作用。     

Chlamydia pneumoniae infection accelerates hyperlipidemia induced atherosclerotic lesion development in C57BL/6J mice

Considerable evidence of an association between Chlamydia pneumoniae infections and cardiovascular disease has emerged. Animal models using genetically altered mice and hypercholesterolemic rabbits have shown a pathogenic role of C. pneumoniae in accelerating atherosclerotic plaque development. In the present study, we evaluated the effect of chronic C. pneumoniae infection on atherosclerosis in C57BL/6J mice, fed either a regular chow diet or a high fat, high cholesterol diet. Infected animals on an atherogenic diet developed significantly larger lesion areas compared with control mice at 18 weeks (2.5-fold increase; 4177+/-777 vs. 1650+/-808 microm(2); P<0.05) and 24 weeks of age (3.3-fold increase; 14139+/-4147 vs. 4298+/-869 microm(2); P<0.02). This study shows that chronic C. pneumoniae infection accelerates atherosclerotic lesion development in diet induced hypercholesterolemic mice, indicating that C. pneumoniae is a co-risk factor of hyperlipidemia in atherogenesis.     

Hybrid C57BL/6J x FVB/NJ mice drink more alcohol than do C57BL/6J mice

BACKGROUND: From several recent strain surveys (28 strains: Bachmanov et al., personal communication; 22 strains: Finn et al., unpublished), and from data in >100 other published studies of 24-hr two-bottle ethanol preference, it is known that male C57BL/6 (B6) mice self-administer about 10-14 g/kg/day and that female B6 mice self-administer about 12-18 g/kg/day. No strain has been found to consume more ethanol than B6. In one of our laboratories (Texas), we noted a markedly greater intake of ethanol in an F1 hybrid of B6 and FVB/NJ (FVB) mice. METHODS: To confirm and extend this finding, we repeated the study at another site (Portland) using concentrations up to 30% ethanol and also tested B6xFVB F1 mice in restricted access drinking procedures that produce high levels of alcohol intake. RESULTS: At both sites, we found that B6xFVB F1 mice self-administered high levels of ethanol during two-bottle preference tests (females averaging from 20 to 35 g/kg/day, males 7-25 g/kg/day, depending on concentration). F1 hybrids of both sexes drank significantly more 20% ethanol than both the B6 and FVB strains. Female F1 hybrids also drank more 30% ethanol. In the restricted access tests, ethanol consumption in the F1 hybrids was equivalent to that in B6 mice. CONCLUSIONS: These data show that this new genetic model has some significant advantages when compared to existing inbred strains, and could be used to explore the genetic basis of high ethanol drinking in mice.     

Characteristics of cardiac aging in C57BL/6 mice

The specific processes that cause aging of the cardiac tissue remain elusive. C57BL/6 (B6) mice are commonly used for investigating age-related diseases in mammals. We thus sought to evaluate the cardiac aging process in B6 mice. Cardiac tissues from the newborn (B6 NB), 2 month-old (B6 2M) and 21–27 month-old B6 mice (B6 aged) were used for the investigation. Several age-related cellular processes were evaluated, including telomere shortening, changes in p53 and p16 expression, changes in mitochondria DNA expression and DNA deletion, and alteration of mitochondria. We found that the aging of the B6 mice cardiac tissue is associated with the maintenance of telomere length, increased expression of p53 and p16, mild changes in mitochondrial DNA expression but widespread DNA deletion, and significant alterations of the mitochondrial ultrastructure within the cardiac tissue. The results of our studies suggest that mitochondrial DNA deletions, which affect the mitochondrial ultrastructure, cytochrome C oxidase activity, and p53 expression, are significantly associated with cardiac aging and may be a source of age-related heart failure.     

Aging is associated with increased T-cell chemokine expression in C57BL/6 mice

To better understand the contribution of the chemokine system in immune senescence, we determined the aging effect on CD4+ and CD8+ T-cell chemokine expression by microarray screening and ribonuclease protection assays. Compared with young C57BL/6 mice, freshly isolated CD4+ cells from aged mice express increased level of interferon-gamma-inducible protein 10 (IP-10), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, regulated upon activation, normal T-cell expressed and secreted (RANTES), and lymphotactin (Ltn). T-cell receptor (TCR)/coreceptor stimulation up-regulates MIP-1alpha, MIP-1beta, and Ltn, and down-regulates IP-10 and RANTES expression in CD4+ T cells. A similar increase in chemokine expression was demonstrated in the CD8+ T cell. Enzyme-linked immunosorbent assays confirmed increased T-cell chemokine protein production in old CD4+ and CD8+ T cells. Finally, supernatant of cultured T cells from old animals caused an enhanced leukocyte chemotaxis response compared with that from young animals, suggesting that the age-related difference in T-cell chemokine expression has an important functional consequence.     

Inflammatory and antioxidant gene expression in C57BL/6J mice after lethal and sublethal ozone exposures

Ozone (O3) is a highly reactive and toxic oxidant pollutant. The objective of this study is to compare cytokine, chemokine, and metallothionein (Mt) changes elicited by lethal and sublethal exposure to ozone in a genetically sensitive strain of mice. Eight-week-old C57BL/6J mice were exposed to 0.3 ppm ozone for 0, 24, or 96 hours; 1.0 ppm ozone for 0, 1, 2, or 4 hours; or 2.5 ppm ozone for 0, 2, 4, or 24 hours. After 24 hours of exposure to 0.3 ppm ozone, increases in mRNA abundance were detected for messages encoding eotaxin, macrophage inflammatory protein (MIP)-1 alpha, and MIP-2. These increases persisted through 96 hours of exposure. At this time point messages encoding lymphotactin (Ltn) and metallothionein were also increased. After 4 hours of 1.0 ppm ozone exposure, increases in mRNA abundance were detected for messages encoding eotaxin, MIP-1 alpha, MIP-2, and interleukin (IL)-6. Mt mRNA abundance was increased after 1 hour of exposure and persisted through 4 hours, although the magnitude of the alterations increased. After 2 hours of 2.5 ppm ozone exposure, increases were detected for messages encoding eotaxin, MIP-1 alpha, MIP-2, IL-6, and Mt. These increases persisted through 4 hours of exposure. Lung weights of mice exposed to 2.5 ppm ozone for 24 hours were approximately 2 times greater than air-exposed mice. At this dose lethality occurred by 36 hours. Increased mRNAs for eotaxin, MIP-1 alpha, MIP-2, and Mt were to a higher magnitude than were detected after 2 and 4 hours of exposure. Messages encoding IL-12, IL-10, interferon (IFN)-gamma, IL-1 alpha, IL-1 beta, and IL-1Ra were unaltered at all time points and doses examined. Our results demonstrate dose- and time-dependent changes in chemokine, cytokine, and Mt mRNA abundance and that early acute changes may be predictive of subacute and chronic responses to ozone.