C57BL/6小鼠食管鳞状细胞癌早期病变的形态学改变

目的:了解食管癌发生过程中的炎症改变.方法:采用100?g/mL的4NQO通过饮水作用于C57BL/6小鼠,分别通过食管拉网脱落细胞法、碘染色法及病理组织学观察第12、16、20、24周等时间段的C57BL/6小鼠食管鳞状细胞癌建模病理的改变.结果:食管拉网脱落细胞法、碘染色法均未观察到小鼠早期食管病变,在实验第12周,纵向解剖食管,通过病理组织学观察到食管上皮不典型增生,第16、20、24周分别观察到原位癌、浸润性鳞癌的发生,在整个肿瘤的发生、发展过程中伴随炎症细胞浸润.结论:食管拉网脱落细胞法、碘染色法不适用于C57BL/6小鼠食管鳞癌建模形态学观察,只能通过病理组织学才能够在不同的时间段观察到食管癌的发生、发展及其炎症改变过程.     

C57BL/6小鼠胶原诱导关节炎的特异性细胞及体液免疫反应

目的观察并比较C57BL/6小鼠初次和加强免疫Ⅱ型胶原后的特异性细胞及体液免疫应答,探讨特异性免疫应答在胶原诱导关节炎发病中的意义。方法用鸡Ⅱ型胶原(CⅡ)在C57BL/6小鼠尾部皮内注射,诱导胶原性关节炎(CIA)。分别取初次免疫后19d及加强免疫后7、28dCIA小鼠脾脏淋巴细胞,CⅡ体外刺激扩增后,采用5-溴脱氧尿嘧啶(BrdU)掺入法和流式细胞术分别测定其扩增情况和表型;并通过流式细胞术测定外周血中细胞内细胞因子干扰素(IFN)-γ、白细胞介素(IL)-4的水平分析Th1和Th2亚群的变化;同时用酶联免疫吸附试验(ELISA)测定不同时期CIA模型血清中抗CⅡ抗体的表达。结果①免疫后不同时间,CIA模型组外周血中CD4+IFN-γ+细胞百分率明显高于对照组(P<0.01),但CIA模型组内不同时间CD4+IFN-γ+细胞百分率差异无统计学意义;②特异性增生实验显示,CIA模型组CD4+T细胞中BrdU+细胞率均高于对照组,但加强免疫后BrdU+细胞率明显低于初次免疫(72±6)%,并且有逐渐降低的趋势;初次免疫后CD4+IFN-γ+细胞百分率为(13±4)%,加强免疫后阳性细胞百分率也下降;③ELISA法测定不同时间血清中CIA模型组抗CⅡ抗体水平,28d吸光度(A)值达到最高,其后逐渐减低,到35d左右(即加强免疫后14d)出现较低的抗体水平。结论C57BL/6小鼠加强免疫反应中特异     

UV致弱日本血吸虫尾蚴诱导C57BL/6小鼠免疫保护作用的研究

目的 研究紫外线（UV）致弱日本血吸虫尾蚴诱导C57BL／6小鼠的免疫保护作用。方法分别观察不同UV强度（300、400和500μW／cm。照射的日本血吸虫尾蚴经腹部皮肤免疫）、不同免疫剂量（8、24和300条uV致弱尾蚴经腹部皮肤免疫）、不同免疫位点（300条UV致弱尾蚴经腹部和耳廓皮肤免疫）和不同免疫次数（100条UV致弱尾蚴经腹部皮肤免疫3次）诱导C57BL／6小鼠抗血吸虫攻击感染（40条正常尾蚴经腹部皮肤感染）的保护力。同时观察免疫后小鼠的体液免疫应答变化。结果 300、400和500μW／cm。UV照射的日本血吸虫尾蚴免疫C57BI。／6小鼠诱导产生的减虫率分别为2．72％、11．37％和10．38％；8、24和300条致弱尾蚴免疫小鼠诱导产生的减虫率分别为38．67％、7．54％和16．36oA；300条致弱尾蚴经腹部和耳廓皮肤免疫诱导小鼠产生的减虫率分别为16．36％和16．14％；100条致弱尾蚴免疫3次，诱导小鼠产生减虫率为4．88％。对300条uV照射尾蚴免疫后小鼠的体液免疫应答动态观察显示，与感染对照组相比，免疫组血清中可溶性成虫抗原（SWA）和可溶性虫卵抗原（SEA）特异的IgG于免疫后2周开始升高，正常尾蚴抗原（SCA）特异的IgG于免疫1周后开始升高，SWA和SCA特异的IgG随免疫次数的增加而升高。结论 UV致弱日本血吸虫尾蚴免疫C57BL／6小鼠能诱导其产生高水平的体液免疫应答，但保护力水平较低，提示C57BL／6小鼠为对UV致弱日本血吸虫尾蚴的低应答品系。     

核因子-κB、细胞间粘附分子-1在C57BL／6小鼠实验性自身免疫性肝炎的表达

核因子（NF）-κB能诱导与免疫和炎症有关的多种细胞因子和粘附分子的表达，细胞间粘附分子-1（ICAM-1）是重要的炎症介质之一，在肝脏炎症、肝纤维化的发生及发展中起重要作用。本研究采用同种肝抗原S-100免疫小鼠，诱导建立实验性自身免疫性肝炎（EAH）模型，观察NF—κB、ICAM-1的表达，探讨NF-κB、ICAM-1在自身免疫性肝损伤中的可能作用机制。     

KLF14基因过表达对改善Hepa1-6小鼠肝癌细胞胰岛素抵抗的作用

目的探讨KLF14基因过表达对小鼠肝癌细胞Hepa1-6胰岛素抵抗的影响。方法实时荧光定量PCR(RT-QPCR)检测KLF14基因m RNA在健康C57BL/6J小鼠各组织的表达分布情况;构建小鼠KLF14基因重组真核表达质粒p IRES2-EGFP-KLF14并转染Hepa1-6细胞,RT-PCR法检测KLF14基因m RNA的表达;Western印迹检测KLF14及p-AKT蛋白水平的表达。结果成功构建p IRES2-EGFP-KLF14质粒;转染肝癌细胞48 h后,KLF14 m RNA和蛋白水平明显高于对照组和空载组(P0.01);转录水平上KLF14基因在小鼠体内普遍表达,其m RNA相对表达量由高到低依次为心脏、骨骼肌、肝脏、脂肪、小肠、肾脏、脑、肺、胃、脾、附睾;非转染组给予血清干预后,正常人血清处理组和糖尿病病人血清处理组无明显差异;而转染组给予血清干预后,糖尿病病人血清处理组p-AKT表达量较正常人血清处理组明显增加;在胰岛素刺激情况下,无论转染组或非转染组,给予PI3K抑制剂LY294002后,p-AKT表达受抑。结论 KLF14在C57BL/6J小鼠多种组织均有表达,提示其可能在维持正常生理功能中发挥一定作用;KLF14基因过表达可促进AKT的活化,并且其增加胰岛素敏感性的作用在糖尿病状态下较正常人更为明显。     

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／     

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。     

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。     

旋毛虫抗小鼠体内SP2/0肿瘤作用的研究

目的观察旋毛虫感染对BAlB/c小鼠体内SP2/0瘤细胞生长的抑制作用。方法用不同剂量、不同方法致弱的旋毛虫感染BALB/c小鼠,在不同时间接种SP2/0细胞,于荷瘤后20 d解剖小鼠,测定小鼠体内肿瘤的体积、重量和无瘤生长小鼠比率,检测T淋巴细胞亚群。结果1)未致弱组、紫外线致弱组和60Co致弱组小鼠肿瘤体积和重量均显著低于对照组(P<0.01),CD4+/CD8+显著高于对照组(P<0.05);无瘤生长小鼠比率显著高于对照组;2)接种750条、500条和250条旋毛虫组肿瘤体积和重量均显著低于对照组(P<0.01),CD4+/CD8+显著高于对照组(P<0.05),无瘤生长小鼠比率显著高于对照组;3)接种3 d1、1 d和21 d后荷瘤组的肿瘤体积和重量均显著低于对照组(P<0.01),CD4+/CD8+显著高于对照组(P<0.05),无瘤生长小鼠比率显著高于对照组。结论未致弱的旋毛虫和经不同方法致弱的旋毛虫对BALB/c小鼠体内的SP2/0骨髓瘤细胞的生长均有抑制作用,接种剂量增加,抑瘤效果越明显,但对实验动物的机体损伤也加重。接种11 d后荷瘤组的抑瘤效果好于接种3 d后荷瘤组和21d后荷瘤组。     

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。     

The effect of melatonin on cleavage rate of C57BL/6 and CB A/Ca preimplantation embryos cultured in vitro

Abstract: There is growing interest in using melatonin as a therapeutic agent for the treatment of a variety of medical conditions, including cancer, heart disease, glaucoma, stress, jet lag, and sleep disorders. In addition, melatonin is being evaluated in a clinical trial to test its efficacy as an oral contraceptive. In order to test any possible adverse effects of melatonin on preimplantation embryos, we used the mouse as a model system. Two strains of mice, a Ped fast , melatonin-deficient strain, C57BL/6, and a Ped slow strain previously found to have detectable melatonin levels at nighttime, CBA/Ca, were studied. Two cell embryos were incubated with melatonin concentrations from 10⁻⁵ M to 10⁻¹³ M for 48 or 72 hours and the number of cells per embryo assessed quantitatively at the end of the incubation period. We used sufficiently high levels of melatonin to mimic the pharmacological concentration used in the oral contraceptive. It was found that there was no effect of melatonin on embryos from either mouse strain at any of the concentrations tested. Our results suggest that if conception occurs while melatonin is being administered to treat a range of conditions, it would not adversely affect the embryo.     

Experimental scoliosis in melatonin-deficient C57BL/6J mice without pinealectomy

The etiology of idiopathic scoliosis is unknown. Scoliosis with many characteristics closely resembling those seen in idiopathic scoliosis has been produced in young chickens and bipedal rats after pinealectomy. In this study, we induced experimental scoliosis in C57BL/6J mice without pinealectomy and melatonin treatment suppressed the development of scoliosis. A total of 100 mice were divided into four groups: 20 quadrupedal mice served as controls; 30 mice underwent resection of two forelegs and tail at 3 wk of age (bipedal mice); the remaining 20 quadrupedal and 30 bipedal mice received intraperitoneal melatonin (8 mg/kg BW) at 19:00 hr daily. Before killing, blood samples were collected in the middle of dark cycle and melatonin levels were measured by radioimmunoassay. Spine X-ray and helical 3D-CT were examined after killing at 5 months of age. The bipedal mice without a tail were able to walk with standing posture, whereas the quadrupedal mice did not walk with standing posture. In C57BL/6J mice, the serum melatonin was reduced to nearly zero; however, the normal level was restored in both bipedal and quadrupedal mice after the injection of melatonin. Scoliosis with rib humps developed in 29 of 30 bipedal and in five quadrupedal mice. None of mice with melatonin treatment developed scoliosis. The results suggest that melatonin deficiency in bipedal mice appears to play crucial role for development of scoliosis. Also the restoration of melatonin levels prevents the development of scoliosis.     

Secretion and effect of somatostatin in early stages of the diabetic syndrome in C57BL/KsJ-mdb mice

Summary In a previous study in C57BL/KsJ (mdb) mice aged 12 to 90 days, we observed alterations in the secretion of insulin and somatostatin and in the inhibitory effect of the latter upon insulin secretion. This study explores whether hormonal alterations are to be found in the very early stages of the diabetic syndrome, i. e. between ages 4 and 12 days. The results demonstrate two distinct phases in the development of the syndrome: (a) up to age 6 days, the perifused slices of pancreata of control animals present biphasic glucose-induced patterns of insulin and somatostatin secretion, whereas the diabetic animals show a diminished first peak of insulin secretion, but a similar pattern of somatostatin secretion, to that of the control animals; (b) between ages 7 and 12 days, the pancreata of diabetic mice exhibit insulin hypersecretion in basal conditions, and an absence of the first secretion peak and insulin hypersecretion in the second phase in response to glucose stimulation. The glucose-induced pattern of somatostatin secretion presents hormonal hypersecretion in both phases. B-cell sensitivity to the inhibitory effect of somatostatin is diminished in mdb mice of the above-mentioned groups, an alteration which becomes more evident as diabetes evolves. The results show that, in very early stages of the evolution of the diabetic syndrome in C57BL/KsJ (mdb) mice, there are already alterations in insulin and somatostatin secretion patterns and in the inhibitory effect of the latter on insulin secretion.     

Naltrexone effects on ethanol reward and discrimination in C57BL/6 mice

The effects of the opioid antagonist, naltrexone, on operant responding for oral ethanol reward delivered on a fixed-ratio schedule, and on the discriminative stimulus properties of intraperitoneally injected ethanol, was examined in two separate experiments. The ages, food/water motivational conditions, and naltrexone doses for the two experiments were similar to allow a direct comparison of naltrexone effects on the two measures. Male food-deprived C57BL/6 mice responded for ethanol during either preprandial (low thirst, high hunger motivation) or postprandial (high thirst, low hunger motivation tests). The reinforcing value of ethanol relative to water was greater during the preprandial tests; however, the amounts of ethanol consumed was greater during the postprandial tests, with some mice becoming unconscious during the 15-min test session. Naltrexone produced dose-responsive reductions in responding for ethanol under either testing condition. During postprandial tests, naltrexone reduced responding for ethanol reward at a dose (1.25 mg/kg) that had little effect on responding for water reward, suggesting some selectivity for ethanol reward. In addition, doses of naltrexone that reduced responding for ethanol rewards did not alter the discrimination of ethanol (g/kg) in an operant discrimination task, but did reduce the total number of responses made during these tests. Thus, under similar motivational and dosing conditions, the opiate antagonist attenuated the reinforcing, but not the discriminative properties of ethanol, suggesting that the latter is mediated by either different or additional neural mechanisms in C57BL/6 mice.     

Evidence of immune system melatonin production by two pineal melatonin deficient mice, C57BL/6 and Swiss strains

Abstract:  We evaluated two pineal melatonin deficient mice described in the literature, i.e., C57BL/6 and Swiss mice, as animal models for studying the immunomodulatory action of melatonin. Plasma melatonin levels in C57BL/6 and Swiss strains were detectable, but lower than levels in control C3H/HENHSD mice. Since these strains are suppose to be pineal melatonin deficient an extrapineal melatonin synthesis may contribute to plasma levels. Regarding cells and tissues from the immune system, all of them were found to synthesize melatonin although at low levels. N-acetyltransferase (AANAT) mRNA was also amplified in order to analyze the alternative splicing between exons 3–4 described for pineal C57BL/6 mice which generates an inclusion of a pseudoexon of 102 bp. For the pineal gland, both the wild type and the mutant isoforms were present in all mice strains although in different proportions. We observed a predominant wild type AANAT mature RNA in thymus, spleen and bone marrow cells. Peripheral blood mononuclear cells (PBMC) culture shown an evident AANAT amplification in all strains studied. Although the bands detected were less intense in melatonin deficient mice, the amplification almost reached the control cell intensity after stimulation with phytohemaglutinin (PHA). In summary, melatonin detection and AANAT mRNA expression in inbred and outbred mice clearly indicate that different cells and tissues from the immune system are able to synthesize melatonin. Thus, the pineal defect seems not to be generalized to all tissues, suggesting that other cells may compensate the low pineal melatonin production contributing to the measurable plasma melatonin level.     

Ethanol increases extracellular dopamine concentration in the ventral striatum in C57BL/6 mice

BACKGROUND: Mesolimbic dopamine is thought to play a role in the reinforcing properties of ethanol, but ethanol-induced changes in extracellular dopamine in the ventral striatum have not been well characterized in mouse models. METHODS: Two experiments were used to characterize the pharmacodynamic response of ethanol in the ventral striatum in C57BL/6 mice. The first experiment determined the effect of ethanol on ventral striatal dopamine in male and female mice after intraperitoneal injection of either 2.0 g/kg ethanol or saline. The second experiment was a replication in males, except that the mice were habituated to intraperitoneal injections before the dialysis experiment. RESULTS: Distinct patterns of dopamine activity in response to ethanol were demonstrated in male and female C57BL/6 mice. A significant increase in dialysate dopamine relative to saline injection was observed in females but not in males. With habituation to intraperitoneal injection before the dialysis experiment, ethanol administration caused a significant dopamine response in males as well. A linear decline was observed in dialysate ethanol concentrations after the peak concentration was reached. Concurrent analysis of the time course of dopamine and ethanol content showed that the dopamine response declined significantly faster than the ethanol concentrations. CONCLUSIONS: The C57BL/6 mouse strain is a justifiable model system for studying the mechanisms involved in ethanol regulation of mesolimbic dopamine activity. Habituation to intraperitoneal injection should be used in male C57BL/6 mice for experiments in which the dopamine response is measured after intraperitoneal injection of a drug. The dissociation between dopamine and ethanol may indicate an acute neural adaptation to ethanol-induced dopamine response in the ventral striatum after a single ethanol injection.