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.     

Morphological and Biochemical Changes During Aging and Photoaging of the Skin of C57BL/6J Mice

The differences between the dorsal skin of 11- and 16-week-old C57BL/6J mice were examined morphologically and biochemically. The dermis of the 16-week-old mice was thinner than that of the 11-week-old mice due to decreases in the amounts of soluble collagen and elastin. Next, the changes in dorsal skin exposed to UVA irradiation for 8 weeks (576 J/cm(2)) were examined in 3 (younger)- and 8 (older)-week-old C57BL/6J mice. The thickness of the dermis was not significantly different between the UVA-irradiated and control mice in either the younger or older group. The increase in the amount of collagen was related to the increase in the level of soluble collagen in the younger mice. In contrast, it was related to the increase in the level of insoluble collagen in the older mice. In the UVA-irradiated older mice, the activity of the latent form of MMP-13 was significantly higher than that in the control mice. These results suggest that aging and UVA-induced photoaging in the skin are histologically and biochemically different phenomena.     

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.     

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.     

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）。     

C57小鼠和C57BL/6 FMR1 KO小鼠剖宫产手术及其仔鼠生长情况的比较研究

目的 C57BL/6小鼠和C57BL/6 FMR1 KO小鼠剖宫产手术及其仔鼠生产情况的比较。方法将C57和FMR1两种小鼠分成两组,每组雌雄按1:1配对,通过剖宫产手术取得仔鼠,C57母鼠作为代乳母鼠,分别比较两种小鼠的妊娠时间、成功受孕时间、7 d成活率、产仔数、离乳率。结果 FMR1小鼠在成功受孕时间、7 d成活率、离乳率上与C57小鼠存在显著差异。结论通过剖宫产净化手术获得FMR1小鼠,为后续开展保种和育种工作提供重要保障。     

An immunohistochemical study of the gastrointestinal endocrine cells in the C57BL/6 mice

The regional distributions and relative frequencies of some gastrointestinal endocrine cells in the eight portions (fundus, pylorus, duodenum, jejunum, ileum, cecum, colon and rectum) of the gastrointestinal tract of C57BL/6 mouse was studied with immunohistochemical method using seven types of specific anti-sera against chromogranin A (CGA), serotonin, somatostatin, human pancreatic polypeptide (HPP), glucagon, gastrin and cholecystokinin (CCK)-8. In this study, all these seven types of immunoreactive (IR) cells were identified. Most of these IR cells in the intestinal portion were generally spherical or spindle in shape (open-type cell) while cells showing round in shape (closed-type cell) were found in the intestinal gland and stomach regions occasionally. Their relative frequencies were varied according to each portion of gastrointestinal tract. CGA-IR cells were demonstrated throughout the whole gastrointestinal tract and they showed most predominant in the pylorus and duodenum. Serotonin-IR cells were detected throughout whole gastrointestinal tract and they showed highest frequency in the stomach and colon. Somatostatin-IR cells were demonstrated throughout whole gastrointestinal tract except for large intestine and showed highest frequency in the fundus. HPP-IR cells were found in the fundus with rare frequency. Peculiarly, glucagon-IR cells were restricted to the fundus, ileum and colon with a few frequencies. Gastrin-IR cells were restricted to the pylorus with numerous frequency and CCK-8-IR cells were observed in the pylorus, duodenum and jejunum with numerous and/or a few frequencies, respectively. In conclusion, some peculiar distributional patterns of gastrointestinal endocrine cells were found in C57BL/6 mouse.     

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.     

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.     

Confirmation and characterization of murine body weight QTLs, Bwq1 and Bwq2, identified in C57BL/6J x KK-Ay/a F2-Ay/a mice

Body weight quantitative trait loci (QTLs), Bwq1 and Bwq2, identified previously in C57BL/6J x KK-Ay/a F2-Ay/a mice, were further confirmed and characterized. Body weight measurement was done from 21 days after birth (Day 21) through Day 100, at 10-day intervals. Bwq1 was statistically significant only on Days 40, 50, and 60, whereas Bwq2 was statistically significant on and after Day 40. When body weight gain (WG) between two successive weight measurements was evaluated, both Bwq1 and Bwq2 were statistically significant only for WG between Days 30 and 40. The results suggest that variations in body weight among F2-Ay/a individuals in later life have been determined by variations in WG during the period shortly after weaning. The results also suggest that Bwq1 is related to increased body weight in the KK strain, because the effect of Bwq1 on the body weight is observed not only in F2-Ay/a, but also in F2-a/a. On the other hand, it is suggested that Bwq2 is related to enhanced obesity caused by Ay mutation and therefore is a genetic modifier that specifically interacts with the Ay allele, because the effect of Bwq2 is only observed in F2-A y/a. There are two candidate genes, Pparg and Hrh1, which are located near the 95% confidence interval of Bwq2, and which are expressed in the adipose tissue; however, we could not find any nucleotide differences in both cDNAs between KK and C57BL/6J strains.     

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.     

Generation of a uniform thymic malignant lymphoma model with C57BL/6J p53 gene deficient mice

Lymphoma is the third most common cancer diagnosed in children, and T-cell lymphoma has the worst prognosis based on clinical observations. To date, a lymphoma model with uniform penetrance has not yet been developed. In this study, we generated a p53 deficient mouse model by targeting embryonic stem cells derived from a C57BL/6J mouse strain. Homozygous p53 deficient mice exhibited a higher rate of spontaneous tumorigenesis, with a high spontaneous occurrence rate (93.3%) of malignant lymphoma. Because tumor models with high phenotypic consistency are currently needed, we generated a lymphoma model by a single intraperitoneal injection of 37.5 or 75 mg/kg N-methyl-N-nitrosourea to p53 deficient mice. Lymphoma and retinal degeneration occurred in 100% of p53^+/− mice administered with higher concentrations of N-methyl-N-nitrosourea, a much greater response than those of previously reported models. The main anatomic sites of lymphoma were the thymus, spleen, bone marrow, and lymph nodes. Both induced and spontaneous lymphomas in the thymus and spleen stained positive for CD3 antigen, and flow cytometry detected positive CD4 and/or CD8 cells. Based on our observations and previous data, we hypothesize that mice with a B6 background are prone to lymphomagenesis.     

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。     

Development of gates to measure the immature platelet fraction in C57BL/6J mice using the Sysmex XN-V series multispecies hematology analyzer

The immature platelet fraction (IPF) is a measure of newly released platelets, which has been used as a marker of platelet production in multiple human studies but is not widely available in multispecies analyzers. We developed gates to measure the IPF in diluted and undiluted murine blood samples on the Sysmex XN-1000V multispecies hematology analyzer. IPF gates were created using undiluted and diluted (1/10) blood samples obtained from adult and newborn (postnatal day 10, P10) C57BL/6J wild-type (WT) mice, and from 3 murine models of thrombocytopenia: c-MPL^−/− mice, which lack the thrombopoietin receptor (hyporegenerative); antibody-mediated thrombocytopenia; and acute inflammation-induced thrombocytopenia. P10 mice were chosen because, at their size, we could consistently obtain (by terminal phlebotomy) the blood volume needed to run an undiluted sample. The undiluted blood IPF gate successfully differentiated between mechanisms of thrombocytopenia in both adult and P10 mice. For diluted samples, 2 IPF gates were generated: a thrombocytopenic (T) gate, which performed well in samples with platelet counts (PCs) <800 × 10⁹/L in adult mice and <500 × 10⁹/L in newborn mice, and a non-thrombocytopenic (NT) gate, which performed well in samples with PCs above these thresholds. PCs and IPFs measured in diluted blood using these gates agreed well with those measured in undiluted blood and had good reproducibility. These diluted gates allow for the accurate measurement of PCs and IPFs in small (10 µL) blood volumes, which can be obtained easily from adult and newborn mice as small as P1 to assess platelet production serially.     

The histopathogenesis of paralytic rabies in six-week-old C57BL/6J mice following inoculation of the CVS-11 strain into the right triceps surae muscle

A fatal encephalomyelitis was developed after intracerebral and hind limb inoculation of in 6-week-old C57BL/6J mice by the inoculation of fixed rabies virus (CVS-11 strain), intracerebrally and into hind. After the intracerebral inoculation, virus antigens were detected in the cerebral cortex and hippocampus at 2 days postinoculation (PI), and later spread centrifugally to thalamus, brain stem, cerebellum, spinal cord and spinal ganglia. At 4 days PI, severe apoptosis and DNA fragmentation were observed in the hippocampus and cerebral cortex. All mice infected intracerebrally were dead without limb paralysis at from 10 to 11 days PI. In contrast, mice infected with virus intramuscularly were persistently observed virus antigens in the myocytes at the site of inoculation from 2 days PI. At 4 days PI, the antigens were demonstrated in the spinal dorsal root ganglia, spinal cord and muscle spindles without their detection in the cerebrum and hippocampus. There were no apoptosis in the spinal cord and dorsal root ganglia, however hind limb paralysis was found in all infected mice. Hind limb paralysis was progressed to quadriparalysis, and mice were dead from 11 to 13 days PI. From 4 days PI, necrosis of neuron was observed in the the spinal and dorsal ganglia with infiltration of lymphocyte. This study suggested that the necrosis of spinal neurons was more important to cause the paralysis of hind limb rather than the severe cerebral infection and apoptosis in C57BL/6J mice infected with CVS-11 strain. The virus primarily replicated in the muscles was ascended the spinal cord via afferent fibers and retrogradely invaded the cerebrum, and with subsequent spread to muscle spindles.     

Quantitative trait loci that control body weight and obesity in an F2 intercross between C57BL/6J and DDD.Cg-Ay mice

I have developed a congenic mouse strain for the A(y) allele at the agouti locus in an inbred DDD/Sgn strain, DDD.Cg-A(y). DDD.Cg-A(y) females are extremely obese and significantly heavier than B6.Cg-A(y) females. The objectives of this study were to determine the genetic basis of obesity in DDD.Cg-A(y) mice, and to determine whether or not their high body weight was due to the presence of DDD background-specific modifiers. I performed quantitative trait locus (QTL) analyses for body weight and body mass index in two types of F(2) mice [F2 A(y) (F(2) mice carrying the A(y) allele) and F(2) non-A(y) (F2 mice without the A(y) allele)] produced by crossing C57BL/6J females and DDD.Cg-A(y) males. The results of the QTL analysis of F(2) A(y) mice were very similar to those obtained for F(2) non-A(y) mice. It was unlikely that the high body weight of DDD.Cg-A(y) mice was due to the presence of specific modifiers. When both F(2) datasets were merged and analyzed, four significant body weight QTLs were identified on chromosomes 6, 9, and 17 (2 loci) and four significant obesity QTLs were identified on chromosomes 1, 6, 9, and 17. Although the presence of DDD background-specific modifiers was not confirmed, a multifactorial basis of obesity in DDD.Cg-A(y) females was thus revealed.     

The response of adipose tissues to Mycoplasma pulmonis and Sendai virus infection in C57BL/6 and DBA/2 mice

Adipose tissues in mammals are categorized into white and brown adipose tissues in which cellular morphology, cell functions, and tissue distribution are different. White adipose tissue (WAT) plays a major role in energy reservation, while brown adipose tissue (BAT) mainly relates to the thermoregulation of the body. One interesting function of adipose tissue is the response to the infection, especially the pathogens that cause pneumonia. We have previously reported that DBA/2 (D2) mice are susceptible to pathogens causing pneumonia, Mycoplasma (M.) pulmonis and Sendai virus (SeV), whereas C57BL/6 (B6) mice are resistant to them. Furthermore, morphological alteration of mediastinal fat tissue (MFT) was seen after infection of M. pulmonis in D2 mice but not in B6 mice. In this study, we aimed to exhibit the difference in adipose tissue response in other areas, including interscapular brown adipose tissue (iBAT), inguinal white adipose tissue (ingWAT), and perigonadal WAT (perigoWAT) between resistant strain, B6 and susceptible strain, D2 after challenging them with M. pulmonis and SeV. Compared with B6 mice, D2 mice showed an increase in fat-associated lymphoid cluster in MFT, an increase in BAT in both iBAT and ingWAT after M. pulmonis and SeV infection. The results of this study indicate that pneumonia caused by M. pulmonis and SeV infection induces browning of adipocyte, suggesting that BAT plays a role in pathogen infection and inflammation.