Ultrastructure of Spermatogonia and Primary Spermatocytes of C57BL6J Mice

The three types of spermatogonia were confirmed. Type A spermatogonia have a large nucleus and loose chromatin and are poor in endoplasmic reticulum. The second type, B spermatogonia, have rounded and smaller nuclei filled with more electron-dense nucleoplasmic material. The endoplasmic reticulum has the aspect of round or elongated cisterns that are free in the cytoplasm or close to the basement membrane. In contrast, intermediate spermatogonia present chromatin material with intermediate condensation compared with the two previous cell types. Primary spermatocytes are characterized by the presence of intercellular bridges and a synaptonemal complex. In the late pachytene stages, the synaptonemal complex was found to be enveloped by chromatin material.     

Piebald mutation on a C57BL/6J background

The classic piebald mutation in the endothelin receptor type B (Ednrb) gene was found on rolling Nagoya genetic background (PROD-s/s) mice with white coat spotting. To examine whether genetic background influenced the phenotype in the piebald mutant mice, we generated a congenic strain (B6.PROD-s/s), produced by repeated backcrosses to the C57BL/6J (B6) strain. Although B6.PROD-s/s mice showed white coat spotting, 7% of B6.PROD-s/s mice died between 2 and 5 weeks after birth due to megacolon. The PROD-s/s, s/s and Japanese fancy mouse 1 (JF1) strains, which also have piebald mutations on different genetic backgrounds with B6, showed only pigmentation defects without megacolon. In expression analyses, rectums of B6.PROD-s/s with megacolon mice showed ~5% of the level of Ednrb gene expression versus B6 mice. In histological analyses, aganglionosis was detected in the rectum of megacolon animals. The aganglionic rectum was thought to lead to severe constipation and intestinal blockage, resulting in megacolon. We also observed an abnormal intestinal flora, including a marked increase in Bacteroidaceae and Erysipelotrichaceae and a marked decrease in Lactobacillus and Clostridiales, likely inducing endotoxin production and a failure of the mucosal barrier system, leading ultimately to death. These results indicate that the genetic background plays a key role in the development of enteric ganglion neurons, controlled by the Ednrb gene, and that B6 has modifier gene (s) regarding aganglionosis.     

补充牛磺酸对高脂饮食C57BL/6J小鼠糖脂代谢的影响

【目的】通过建立高脂动物模型,探究牛磺酸对肥胖小鼠糖脂代谢的影响。【方法】将20只5周龄SPF级C57BL/6J雄性小鼠随机分为4组：空白组、模型组、3%牛磺酸组和5%牛磺酸组,每组5只,试验期为15周。空白组小鼠饲喂对照饲粮,模型组饲喂高脂饲粮,其余两组在模型组饲粮的基础上分别添加3%、5%的牛磺酸。试验结束前2周分别进行口服葡萄糖耐受实验（OGTT）和胰岛素耐受实验（ITT）。试验结束后乙醚麻醉眼球取血,采用颈椎脱臼法处死小鼠,采集肝脏、肾脏、脾脏、附睾脂肪组织并称重,计算脏器/脂肪系数。测定血清中各项生化指标及瘦素（LEP）、脂联素（ADPN）含量,以及肝脏中甘油三酯（TG）、总胆固醇（TC）的含量,采用油红O染色和苏木精-伊红（HE）染色分别观察肝脏脂滴分布和脂肪组织形态变化。【结果】①与空白组相比,模型组小鼠体重极显著增加（P<0.01）,血糖（GLU）及血脂指标出现异常,葡萄糖耐受和胰岛素耐受的曲线下面积极显著升高（P<0.01）,符合肥胖模型的特征。②与模型组相比,添加牛磺酸后小鼠总增重、肝脏系数和脂肪系数均极显著降低（P<0.01）;血清中丙氨酸转氨酶（ALT）、天冬氨酸转氨酶（AST）活性及低密度脂蛋白（LDL）含量极显著升高（P<0.01）,GLU含量显著下降（P<0.05）;肝脏中TG和TC含量极显著下降（P<0.01）,ADPN含量极显著升高（P<0.01）;葡萄糖耐受和胰岛素耐受的曲线下面积均极显著降低（P<0.01）;肝脏中的脂滴数量减少,脂肪细胞的细胞截面积极显著减小（P<0.01）,细胞数量极显著增多（P<0.01）,脂肪细胞分布较均匀。【结论】牛磺酸可通过调节高脂饮食诱导的肥胖小鼠糖脂代谢水平,改善其肝脏及脂肪的组织病理形态,可能对肝脏具有保护作用。     

Pigmentation of the aortic and pulmonary valves in C57BL/6J x Balb/cByJ hybrid mice of different coat colours

Neural crest‐derived melanocytes have been recorded in several parts of the mammalian heart but not in the pulmonary valve. We report here the presence of melanin‐containing cells in the leaflets (cusps) of both the aortic and pulmonary valves. A total of 158 C57BL/6J x Balb/cByJ hybrid mice exhibiting four coat colours, namely black, white, agouti and non‐agouti brown, were examined. We sought for any relationship between the presence of melanocytes in the valves and the coat colour of the animals. The pigmentation levels of the leaflets were accomplished using a scale of five pigment intensities. White mice lacked pigment in the heart. In 10.5% of the remaining animals, there were melanocytes in the pulmonary valve leaflets. Thus, this is the first study to report the presence of such cells in the pulmonary valve of mammals. Melanocytes occurred in the leaflets of the aortic valves of 87.2% of mice. The incidence of melanocytes and the pigmentation level of the leaflets did not statistically differ according to the coat colours of the animals. This disagrees with previous observations, indicating that the amount of melanocytes in the heart reflects that of the skin. The incidence and distribution of melanocytes in aortic and pulmonary valves are consistent with the notion that the formation of the arterial valves is mediated by specific subpopulations of neural crest cells. We hypothesize that melanocytes, even not producing melanin, may be more frequent in the heart than previously thought, exerting presumably an immunological function.     

Anti-obesity activity of diglyceride containing conjugated linoleic acid in C57BL/6J ob/ob mice

This study was to investigate the anti-obesity effects of diglyceride (DG)-conjugated linoleic acid (CLA) containing 22% CLA as fatty acids in C57BL/6J ob/ob male mice. There were four experimental groups including vehicle control, DG, CLA, and DG-CLA. The test solutions of 750 mg/kg dose were orally administered to the mice everyday for 5 weeks. CLA treatments significantly decreased mean body weight in the obese mice throughout the experimental period compared to the control (p < 0.01). All test solutions significantly decreased the levels of triglyceride, glucose and free fatty acids in the serum compared with control (p < 0.05). The levels of total cholesterol were also significantly reduced in DG and DG-CLA groups compared with the control group (p < 0.05). CLA significantly decreased weights of renal and epididymal fats compared with the control (p < 0.05). DG and DG-CLA also significantly decreased the epididymal fat weights compared with the control (p < 0.05). A remarkable decrease in the number of lipid droplets and fat globules was observed in the livers of mice treated with DG, CLA, and DG-CLA compared to control. Treatments of DG and CLA actually increased the expression of peroxisome proliferator-activated receptor gamma. These results suggest that DG-CLA containing 22% CLA have a respectable anti-obesity effect by controlling serum lipids and fat metabolism.     

SPRN0/0型小鼠与C57BL/6野生型小鼠小脑中microRNA的差异表达

The purpose of this study was to identify different expression of microRNAs between cerebellum of SPRN^0/0 mice and C57BL/6 wild mice, and investigate relative expression results of microRNA in cerebrum of SPRN^0/0 mice by Real-time PCR technology. The results showed that compared with cerebellum of C57BL/6 wild mice, eight microRNAs were decreased significantly:miR-135a, miR-24-2*, miR-146a, miR-7a, miR-380, miR-448, miR-128 and miR-152. miR-24-2* fold change to more than 10, five microRNAs including miR-448,miR-146a,miR-128,miR-380 and miR-152 fold change to more than 2, miR-135a and miR-7a fold change to more than 1. Thus, we concluded that these changes of microRNAs expression might be involved in Shadoo protein function and the establishment of target genes of microRNAs might provide new ideas for researching Shadoo protein function.     

C57BL/6J小鼠非酒精性脂肪肝模型的建立

本试验分别采用高脂饲料和高脂饲料复合四氯化碳对C57BL/6J小鼠进行诱导,研究建立非酒精性脂肪肝模型的条件.本试验将C57BL/6J小鼠分成高脂组、高脂复合四氯化碳组(复合组)和正常组.各组分别于饲喂4、6、8周处死5只,称小鼠体重与肝重,采血测血清中生化指标情况,并取肝脏做H.E.染色、油红O染色.通过肝指数、生化与病理检查等指标,评价非酒精性脂肪肝的进程.结果显示,随着饲喂时间加长,高脂组动物肝脏脂肪变性加重;复合组动物除肝脏脂肪变性外,出现纤维化和明显的炎性浸润;4周时,高脂组中脂肪变性比复合组明显.6～8周时高脂组和复合组中生化指标明显高于正常组.本试验经饲喂高脂饲料成功复制了小鼠非酒精性脂肪肝模型.     

C57BL/6J小鼠亚慢性镉中毒模型的建立

为了建立小鼠亚慢性镉中毒模型,本研究将20只C57BL/6J雄性小鼠随机分为4个剂量组和溶剂对照组,每组隔天分别腹腔注射含0.25、0.5、1和2 mg/kg剂量的氯化镉溶液和等量去离子水(溶剂),共染毒4周,观察不同剂量的镉离子对雄性小鼠肝脏、肾脏、睾丸的损伤情况.结果各处理组小鼠体质量增长要比对照组慢,脏器系数与对照组相比也有显著差异,处理组小鼠肝脏、肾脏、睾丸中镉含量显著高于对照组.病理组织切片结果表明,各处理组中小鼠的肝脏、肾脏、睾丸组织均出现不同程度的损伤.氯化镉可以显著地抑制小鼠体质量增长,并对小鼠的脏器系数产生影响,腹腔注射后在肝脏、肾脏、睾丸组织中产生蓄积,并对其造成一定损伤.隔天腹腔注射2 mg/kg剂量的氯化镉,4周可建立较理想的小鼠镉中毒模型.     

SPF级BALB/cC57BL/6小鼠繁殖性能及生长发育的比较研究

为提高SPF级实验动物的质量,选择10周龄BALB/c C57BL/6小鼠各50只（雌雄各半）,采取雌雄1？1近亲交配繁殖,并统计其生长发育和繁殖性能指标。BALB/c小鼠1～3周龄的平均窝重及离乳后的体重增长明显大于C57BL/6小鼠（p〈0.01）。第1胎交配分娩间隔,第1和第3胎离乳育成率品系间差异均有显著性（P〈0.05及P〈0.01）。BALB/c小鼠的体格比C57BL/6小鼠大,带乳能力比C57BL/6小鼠强但产仔能力比C57BL/6小鼠弱。     

Unilateral perinephric pseudocyst secondary to hydronephrosis in a C57BL/6J mouse

A 9-month-old C57BL/6J mouse had progressive abdominal distension over a 1-week period, and a distended left renal capsule was discovered at postmortem examination. Incision of the capsule showed a tan, cloudy fluid that separated the renal capsule and the remnant left kidney. Microscopically, the capsule was significantly separated from the renal parenchyma by clear space and necrotic cellular debris. The majority of the lining of the renal capsule was composed of fibrous connective tissue and lacked an epithelial lining, consistent with a subcapsular perinephric pseudocyst. In addition, attached to intermittent portions of the renal capsule were thin rims of compressed cortical tissue lined by transitional epithelium. The finding of remnant cortical tissue lined by transitional epithelium is consistent with severe hydronephrosis and indicates that the hydronephrosis preceded the formation of the perinephric pseudocyst. To our knowledge, this is the first case report to characterize a perinephric pseudocyst secondary to severe hydronephrosis in a mouse.     

FNDC5在小鼠老龄化过程脂肪组织中的表达变化

本研究旨在探讨Ⅲ型纤连蛋白域包含蛋白5（type Ⅲ fibronectin domain contains protein 5,FNDC5）在小鼠老龄化过程中脂肪组织中的表达变化,以小鼠老龄化过程中不同发育阶段的健康小鼠为研究对象,通过HE染色、免疫组织化学染色、实时荧光定量PCR和Western blotting等技术研究小鼠老龄化过程中脂肪组织FNDC5的表达以及定位。结果发现,FNDC5在小鼠老龄化过程中各个发育时期的脂肪中均有不同程度的表达并呈现明显的差异性。HE染色发现,随着年龄的增长,脂肪细胞的大小呈现先逐渐增大后萎缩的趋势。免疫组织化学染色发现,FNDC5在幼年小鼠的脂肪组织中表达水平最高,在性成熟的脂肪组织中表达水平次之,老年的脂肪组织中的表达水平低于性成熟时期,体成熟的脂肪组织中表达水平最低。实时荧光定量PCR和Western blotting检测结果也与免疫组织化学染色趋势相符。以上结果表明,FNDC5基因可能在脂肪组织中发挥一定的作用,为研究脂肪代谢以及肥胖相关的疾病提供新思路。     

Expression Changes of FNDC5 in Adipose Tissue During Aging Process in Mice

In order to investigate the expression changes of type Ⅲ fibronectin domain contains protein 5 (FNDC5) in adipose tissue of mice during aging process,healthy mice at different developmental stages were used as research objects.In this experiment,HE staining,immunohistochemical staining,Real-time PCR and Western blotting techniques were used to study the expression and localization of FNDC5 in adipose tissue during aging process.The results showed that FNDC5 was expressed to varying degrees in the fats of all developmental stages in the aging process of mice and showed significant differences.HE staining showed that with age,the size of fat cells gradually increased and then shrank.Immunohistochemical staining showed that the expression level of FNDC5 in adipose tissue of young mice was the highest,followed by that of sexual mature adipose tissue,and that of aged adipose tissue was lower than that of sexual maturation,and the expression level of FNDC5 was the lowest in mature adipose tissue of young mice.Subsequent Real-time PCR and Western blotting results were also consistent with immunohistochemical staining trends.The above results indicated that the FNDC5 gene might play a certain role in adipose tissue,which would provide new ideas for the study of fat metabolism and obesity-related diseases.     

Evaluation of host and bacterial gene modulation during Lawsonia intracellularis infection in immunocompetent C57BL/6 mouse model

BackgroundProliferative enteritis caused by Lawsonia intracellularis undermines the economic stability of the swine industry worldwide. The development of cost-effective animal models to study the pathophysiology of the disease will help develop strategies to counter this bacterium.ObjectivesThis study focused on establishing a model of gastrointestinal (GI) infection of L. intracellularis in C57BL/6 mice to evaluate the disease progression and lesions of proliferative enteropathy (PE) in murine GI tissue.MethodsWe assessed the murine mucosal and cell-mediated immune responses generated in response to inoculation with L. intracellularis.ResultsThe mice developed characteristic lesions of the disease and shed L. intracellularis in the feces following oral inoculation with 5 × l0⁷ bacteria. An increase in L. intracellularis 16s rRNA and groEL copies in the intestine of infected mice indicated intestinal dissemination of the bacteria. The C57BL/6 mice appeared capable of modulating humoral and cell-mediated immune responses to L. intracellularis infection. Notably, the expression of genes for the vitamin B12 receptor and for secreted and membrane-bound mucins were downregulated in L. intracellularis -infected mice. Furthermore, L. intracellularis colonization of the mouse intestine was confirmed by the immunohistochemistry and western blot analyses.ConclusionsThis is the first study demonstrating the contributions of bacterial chaperonin and host nutrient genes to PE using an immunocompetent mouse model. This mouse infection model may serve as a platform from which to study L. intracellularis infection and develop potential vaccination and therapeutic strategies to treat PE.     

流行性乙型脑炎病毒GI型毒株SD12在C57BL/6小鼠体内的动态分布研究

为了解流行性乙型脑炎病毒基因I型毒株SD12在感染C57BL/6小鼠体内的病毒分布,应用qRT-PCR 方法检测该毒株在小鼠体内各组织的动态分布情况。结果显示腹腔感染组中2 dpi仅能在心脏和脾脏检测出病毒核酸,5～7 dpi能够在心脏、肝脏、脑部、盲肠和扁桃体检测到病毒核酸。血脑屏障受损的腹腔感染组中最早2 dpi在肠系膜淋巴结中检测到病毒核酸,3 dpi基本能在各组织中检测到病毒核酸,5～7 dpi在大脑中检测到大量病毒核酸。所有对照组没有检测到病毒阳性核酸。本研究表明基因I型流行性乙型脑炎病毒感染血脑屏障受损的C57BL/6小鼠后能迅速入侵各组织脏器,主要浸染肝脏、肺脏、肾脏、盲肠和大脑。拥有完整血脑屏障的小鼠对病毒具有一定抵抗能力,病毒在各组织中的含量相对比较低。     

Muscle lesions in beige (Chediak-Higashi syndrome) and heterozygous C57BL/6J mice

Muscles from male and female C57BL/6J Chediak-Higashi syndrome (CHS) and phenotypically normal mice with the bgJ allele were studied microscopically and histochemically for the presence of basophilic cytoplasmic structures seen by other investigators in muscles of CHS mice of the SB/Le strain. Triceps brachii, gastrocnemius, quadriceps femoris, and biceps femoris muscles were examined. Multiple basophilic cylindrical lesions were present in hematoxylin and eosin-stained muscle from all groups. Lesions were positive for esterase, Sudan black, and periodic acid-Schiff. Lesions were only seen in type II muscle fibers. Type I muscle cells comprised less than an estimated 5% of the total muscle fibers in the four muscles examined. Scores were assigned based on the presence or absence of lesions in each muscle. Male mice of both phenotypes had significantly more lesions (P less than 0.05) than female mice. When sexes were combined, lesions were significantly (P less than 0.05) more numerous in normal mice than CHS mice for all muscles except the gastrocnemius. Lesions were significantly (P less than 0.05) more numerous in the phenotypically normal male than the CHS male mice for the triceps and quadriceps muscles. There was no significant difference (P greater than 0.05) between lesions of phenotypically normal female and female CHS mice. Basophilic cytoplasmic structures did not prove to be a manifestation of the CHS trait.     

Development, structure, and keratin expression in C57BL/6J mouse eccrine glands

Eccrine sweat glands in the mouse are found only on the footpads and, when mature, resemble human eccrine glands. Eccrine gland anlagen were first apparent at 16.5 days postconception (DPC) in mouse embryos as small accumulations of cells in the mesenchymal tissue beneath the developing epidermis resembling hair follicle placodes. These cells extended into the dermis where significant cell organization, duct development, and evidence of the acrosyringium were observed in 6- to 7-postpartum day (PPD) mice. Mouse-specific keratin 1 (K1) and 10 (K10) expression was confined to the strata spinosum and granulosum. In 16.5 and 18.5 DPC embryos, K14 and K17 were both expressed in the stratum basale and diffusely in the gland anlagen. K5 expression closely mimicked K17 throughout gland development. K6 expression was not observed in the developing glands of the embryo but was apparent in the luminal cell layer of the duct by 6 to 7 PPD. By 21 PPD, the gland apertures appeared as depressions in the surface surrounded by cornified squames, and the footpad surface lacked the organized ridge and crease system seen in human fingers. These data serve as a valuable reference for investigators who use genetically engineered mice for skin research.     

C57BL/6J等近交系小鼠精子冷冻研究进展

小鼠精子冷冻方法虽成功建立多年,但C57BL/6J等近交系小鼠的精子在冻融后的成活率和受精率远远低于封闭群和杂交小鼠的精子。C57BL/6J等近交系小鼠的精子冷冻方法已成为当前大量增加转基因小鼠保种的一个瓶颈,同时成为国内、外近来研究的热点。本文系统介绍了近年国外为改进C57BL/6J等近交系小鼠精子冷冻保存所的做努力和探索。研究包括:各种冷冻保存方法;新培养基的改良;各种冷冻试剂组合;冷冻对小鼠精子质膜伤害机理的研究及其保护方法;以及提高冻融后精子获能和提高授精能力等领域。     

Outbreak of abdominal distension and obstipation in a C57BL/6J experimental autoimmune encephalomyelitis study

Seventy-four 9-week old female C57BL/6J mice housed in a conventional facility were manipulated to induce experimental autoimmune encephalomyelitis, among which 26 developed clinical signs including lethargy, absence of defecation, and abdominal distension. By gross necropsy examination, there was distension of the cecum and colon with fecal impaction. By histologic examination, there was severe ulcerative and proliferative typhlocolitis. Fecal ELISA confirmed the presence of toxins A and B of Clostridium difficile. Alteration in immune status of the immunocompetent mice, due to stress caused by experimental manipulation or autoimmune disease, may have led to intestinal dysbiosis, followed by opportunistic infections resulting in C. difficile-associated disease. This report brings to light the occurrence of the disease in immunocompetent laboratory mice during experimental manipulations associated with alteration in immune status, and it discusses potential hazards associated with conventional housing within a hospital-associated research institute.     

对C57BL／6小鼠超排效果的研究

本文以近交系C57BL／6小鼠为实验对象．研究注射不同剂量的PMSG和hCG对小鼠超排效果的影响。取C57BL／6小鼠各30只,按照注射剂量不同分为A、B、C三组,每组10只,A组注射PMSG2．5IU,HCG2．5IU,B组注射PMSG5．0IU,HCG5．0IU,C组注射PMSG7．5IU,HCG7．5IU。每只小鼠腹腔注射PMSG,间隔48h后分别注射HCG进行超数排卵,再与性成熟同系公鼠合笼,次日早上检查阴道栓．有栓雌鼠用颈椎脱臼法处死。在实体显微镜下由输卵管膨大部冲卵．收集卵母细胞置于盛有M2培养液的表面皿中检查计数．分析超排效果。结果表明。C57BU6小鼠B组的平均取卵数极显著高于A组的平均取卵数（P〈0．05）;B组的平均取卵数显著高于C组的平均取卵数（P〈0．05）;C组与A组的平均取卵数差异不显著（P〉0．05）。     

Heme oxygenase-1 activity is involved in the control of Toxoplasma gondii infection in the lung of BALB/c and C57BL/6 and in the small intestine of C57BL/6 mice

Heme oxygenase-1 (HO-1) is an enzyme that catabolizes free heme, which induces an intense inflammatory response. The expression of HO-1 is induced by different stimuli, triggering an anti-inflammatory response during biological stress. It was previously verified that HO-1 is able to induce indoleamine 2,3-dioxygenase (IDO), an enzyme that is induced by IFN-γ in Toxoplasma gondii infection. To verify the role of HO-1 during in vivo T. gondii infection, BALB/c and C57BL/6 mice were infected with the ME49 strain and treated with zinc protoporphyrin IX (ZnPPIX) or hemin, which inhibit or induce HO-1 activity, respectively. The results show that T. gondii infection induced high levels of HO-1 expression in the lung of BALB/c and C57BL6 mice. The animals treated with ZnPPIX presented higher parasitism in the lungs of both lineages of mice, whereas hemin treatment decreased the parasite replication in this organ and in the small intestine of infected C57BL/6 mice. Furthermore, C57BL/6 mice infected with T. gondii and treated with hemin showed higher levels of IDO expression in the lungs and small intestine than uninfected mice. In conclusion, our data suggest that HO-1 activity is involved in the control of T. gondii in the lungs of both mouse lineages, whereas the hemin, a HO-1 inducer, seems to be involved in the control of parasitism in the small intestine of C57BL/6 mice.