A huge amount of experimental data from past studies has played a vital role in the development of new knowledge and technologies in biomedical science. The importance of computational technologies for the reuse of data, data integration, and knowledge discoveries has also increased, providing means of processing large amounts of data. In recent years, information technologies related to “ontologies” have played more significant roles in the standardization, integration, and knowledge representation of biomedical information. This review paper outlines the history of data integration in biomedical science and its recent trends in relation to the field of experimental animal science.

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Mammalian quantitative traits that are observed at the whole-body level, such as body weight and length and blood biochemical parameters, are determined by the cooperative effects of multiple genetic and epigenetic factors as well as environmental factors. This complexity has hampered the genetic analysis of quantitative traits. To overcome this difficulty, we have established a full set of consomic mouse strains, also known as chromosome substitution strains, by replacing every chromosome of the classical inbred strain C57BL/6J with its counterpart from the Japanese wild-mouse-derived inbred strain MSM/Ms. The core components of the genomes of these two strains originated from different mouse subspecies. The inter-subspecific large-genome divergence and phenotypic differences between the two strains allowed the identification of genetic determinants for many quantitative traits by comprehensive phenotype screening. For some quantitative traits, the genetic determinants could be dissected into multiple chromosomes, thereby reflecting strain differences between C57BL/6J and MSM/Ms and their simple additive effects on the background of the consomic host strain. For other quantitative traits, the measured values of some consomic strains often far exceeded the range of the two parental strains, which suggests that nonadditive genetic interactions occur among multiple genes located on the substituted MSM/Ms chromosomes and the consomic host chromosomes. Thus, the inter-subspecific consomic strains are unique tools that can be used to identify both additive and nonadditive genetic effects on quantitative complex traits.

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The common marmoset (Callithrix jacchus) is a species of New World monkeys. Because of its ease of maintenance and breeding in laboratories, use of the marmoset is growing rapidly in biomedical research. In neuroscience, the marmosets are attracting more attention, since they have the developed cerebral cortex which plays a key role in higher brain functions. In this review on neuroscience research using the marmoset, experimental techniques developed in our laboratory are summarized. We introduce artificial rearing of neonates, stereotaxic surgery, neuroanatomy including virtual microscopy based on the Internet technology, behavioral study using a large number of marmosets, and primary neuron culture study.

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Calcium ions play an important role in several cell functions, from fertilization to cell death. The cytosolic Ca²⁺ concentration is much lower than the extracellular concentration ([Ca²⁺]_o). The latter may markedly affect Ca²⁺ fluxes across the cell membrane and thus the cellular Ca²⁺ load. Thus, when working with preparations in vitro, it is important to keep [Ca²⁺]_o close to the in vivo value. In this study, we determined the calcemia in immature rats, for which values are currently unavailable, and investigated how supraphysiological [Ca²⁺]_o affects myocardial Ca²⁺ handling. Blood ionized [Ca²⁺] was similar in neonatal (2–5 days old) and adults Wistar rats (1.28 ± 0.03 and 1.31 ± 0.03 mmol/l; n=6 and 5, respectively, P>0.37), and lower than the [Ca²⁺]_o range often used in experiments with neonatal myocardial preparations. Cytosolic Ca²⁺ transients, measured with indo-1 in neonatal ventricular myocytes, were enhanced by an increase in [Ca²⁺] _o from 1.2 to 2 mM, which also increased the Ca²⁺ content in the sarcoplasmic reticulum (SR), and changed the pattern of competition between the main transporters that remove Ca²⁺ from the cytosol (SR Ca²⁺-ATPase and Na⁺/Ca²⁺ exchanger). These observations stress the importance of using physiological [Ca²⁺]_o values for reliability of results. It is expected that the present calcemia data, reported for the first time in immature rats, may contribute to the refinement of in vitro experiments with neonatal rat preparations.

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In order to identify potential unanticipated side reactions and immune responses, the evaluation of candidate vaccines should include immunization of the murine model of the disease in question and mutant animals, as well as normal laboratory animals. We employed WBB6F₁-W/W^v and WBB6F₁-Sl/Sl^d mutant mice, which are genetically mast cell deficient and lack intestinal pacemaker activity due to a severe deficiency in interstitial cells of Cajal. Antigen-specific mucosal and systemic immune responses in the mutant and congenic normal mice were induced by intranasal or intragastric immunization with ovalbumin (OVA) plus cholera toxin as an adjuvant. It was found that the levels of the OVA-specific humoral immune response in the mucosal and systemic tissues of the mutant mice immunized intranasally were roughly equivalent to those of the congenic normal mice. In contrast, the specific humoral immune response in the intragastrically immunized mutant mice was greater than that observed in the congenic normal mice. Unexpectedly, the titers of OVA-specific IgA antibodies and total IgA antibodies in the fecal extracts of both intranasally and intragastrically immunized mutant mice were significantly lower than in those of the congenic normal mice. Although the detailed mechanisms leading to these differences remain unclear, the unexpected immune responses observed in the gastrointestinal tracts of the mice in this study may be related to an abnormality of gastrointestinal motility. Our data therefore suggest that studies using mutant mice and physiological assessments should be carried out during mucosal vaccine development.

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This study established an experimental mouse model of trauma-hemorrhagic shock (THS). THS-induced mice (C57BL/6J, n=33) were subjected to femoral fracture, ischemia for 90 min, and resuscitation for 15 min. The sham-operated mice (C57BL/6J, n=33) underwent the same anesthetic and surgical procedures, but neither trauma-hemorrhage nor fluid resuscitation were performed. Mean arterial pressure (MAP) and microvascular tissue perfusion over the small intestine, liver, and left kidney were longitudinally measured in all mice. Blood was collected for analysis at baseline and 3, 6, 12, and 24 h post resuscitation, and the small intestine, liver, and left kidney were resected for hematoxylin and eosin staining 24 h post resuscitation. Compared with the sham group, MAP and microvascular tissue perfusion over the small intestine, liver, and left kidney were all significantly reduced in the THS group at the end of hemorrhage. Following resuscitation, no significant differences were observed between the groups. THS induction was associated with significantly increased plasma concentrations of Cr, AST, CPK, IL-6, IL-10, and TNF-α from the baseline values by two- to three-fold after the hemorrhage phase, and THS-induced mice demonstrated significantly increased histological injury scores. The rapid drop in MAP and microvascular tissue perfusion observed following THS induction, and the gradual recovery post resuscitation, reflects the successful establishment of a THS experimental mouse model.

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As the in vivo function of bone marrow-engrafted umbilical cord blood (UCB)-derived mesenchymal cells (UCBCs) after UCB transplantation is unknown, we examined in vivo osteoblastic differentiation using mouse UCB transplantation and fracture models. UCBCs obtained from GFP transgenic mice were intravenously injected into irradiated C57BL/6 mice. After three months, the in vivo osteoblastic differentiation potential of bone marrow-engrafted UCBCs was examined histologically using a mouse fracture model. GFP-positive UCBCs were detected in the bone marrow of recipient mice. On day 7, UCBCs were observed in the fracture gap and surrounding the titanium screws of the fixation device. The UCBCs were also positive for alkaline phosphatase and von Kossa staining. By day 14, UCBCs were observed around and within a formed intramedullary callus. The newly formed woven bone consisted of ALP- and von Kossa-positive cells. Our findings suggest that UCBCs contribute to the fracture healing process after bone marrow engraftment and that UCBC transplantation can fully reconstruct not only hematopoietic cells but also mesenchymal cell lineages.

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We screened for natural mutations in Crl:CF1 closed colony mice using an ordinary backcrossing system. Five of 30 CF1 males carried novel genes that caused white spots on colored coats. Their backcross progenies showed a white spot phenotype. The white spot gene was mapped to approximately 39 cM on chromosome 5, where the Kit gene is known to reside. Allelism testing between this spot gene and the Kit gene was performed using two already known Kit alleles, Kit^W, and Kit^W-v. We demonstrated that the spot mutation was semidominant and a novel allele of the Kit gene, which was tentatively named Kit^W-Ham. No infertility or anemia was observed in Kit^W-Ham homozygotes. However, a reduced number of germ cells and mast cells was observed in Kit^W-Ham/Kit^W and Kit^W-Ham/Kit^W-v transheterozygotes. Sequencing of the 21 exons of the Kit gene in the Kit^W-Ham mutants revealed that a unique guanine-to-adenine (G-A) transition at nucleotide position 545 (c.545G>A) of exon 3 changes arginine (R) to glutamine (Q) at position 182 in the extracellular domain of the KIT protein (p.R182Q). This extracellular KIT domain is a binding site for stem cell factors (SCF). It was concluded that the Kit^W-Ham mutant may serve as a new model of human piebaldism.

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Bioluminescence imaging (BLI) has been applied in gene therapy and research to screen for transgene expression, progression of infection, tumor growth and metastasis, and transplantation. It enables real-time and relatively noninvasive localization and serial quantification of biological processes in experimental animals. In diabetes research, BLI has been employed for the quantification of β-cell mass, monitoring of islet graft survival after transplantation, and detection of reporter gene expression. Here, we explore the use of BLI in a transgenic mouse expressing luciferase under the control of the mouse insulin 1 promoter (MIP-Luc-VU). A previous report on MIP-Luc-VU mice showed luminescence intensities emitted from the islets correlated well with the number of islets in vitro and in vivo. In this study, we showed MIP-Luc-VU mice fed a high fat diet for 8 weeks gave rise to a greater bioluminescent signal than mice fed a regular diet for the same period of time. Conversely, there was a strong reduction in the signal observed in diabetic Mafa-deficient/Mafk-transgenic mutant mice and streptozotocin-treated mice, reflecting the loss of β-cells. Furthermore, we were able to monitor fetal β-cell genesis in MIP-Luc-VU mice during the late gestational stage in a noninvasive and repetitive manner. In summary, we show that bioluminescence imaging of mice expressing a β-cell specific reporter allows detection of changes in β-cell mass and visualization of fetal β-cell neogenesis in uteri.

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In this paper, the mouse pup-in-a-cup model was improved for younger mouse pups, and the effect of artificial rearing on gut microbiota development was evaluated. Intragastric cannulas were placed through the esophagus into 3-day-old C57BL/6J mice (n=48), and the mice were artificially reared (AR) with mouse milk substitute (MMS). Littermate pups (n=20) were maternally reared (MR) as controls. The feces of 3-day-old pups were analyzed by combining the PCR-denaturing gradient gel electrophoresis (DGGE) fingerprinting technique and sequencing of 16s rRNA gene fragments. After 11 days of artificial rearing, 37 of 48 pups were still alive. There were no significant changes in the number of DGGE bands or the Shannon index between the two groups. However, several bands in the AR group were obviously different from those in the MR group in the DGGE profile. These results demonstrate that it is possible to implant intragastric cannulas into 3-day-old C57BL/6J mice pups. However, the variation in the gut microbiota composition is non-negligible, even though the AR pups grow well.

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The purpose of the present study was to characterize Himalayan marmot lipoprotein profiles and investigate their response to an atherogenic diet. Sixteen marmots were randomly divided into two groups. The control group was fed with a standard chow diet, and the other group was fed with a chow diet containing 0.3% cholesterol, 6.7% lard, and 3.3% corn oil (designated as HFCD) for 16 weeks. The plasma lipids were measured, and lipoprotein profiles were analyzed. With the chow diet, the major lipoproteins were high density lipoproteins. HFCD feeding increased not only plasma total cholesterol levels but also body weight compared with the control group (P<0.05). Plasma lipoprotein (a) was detected in marmots, and the plasma lipoprotein (a) levels were 4.5-fold higher after being fed HFCD for 16 weeks. However, atherosclerotic lesions were not found in the aorta of HFCD-fed marmots. This study suggested that marmots are HDL-rich mammals and resistant to HFCD-induced atherosclerosis.

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The aim of this study was to collect data on chronological changes in clinical laboratory tests, pathological examinations, and hepatic drug-metabolizing enzymes from Wistar Hannover rats at 8, 10, 19, and 32 weeks of age. The serum triglyceride concentration and the serum LDL cholesterol level were higher in males than in females at all ages. In contrast, serum total protein and creatinine concentrations and cholinesterase activity were lower in males than in females. In addition, sex differences were confirmed in pituitary weight and hepatic CYP3A2 and CYP2C11 activities. In conclusion, the general toxicological data noted in clinical laboratory tests, pathological examinations, and hepatic drug-metabolizing enzymes relating to chronological changes and sex differences may be useful in assessing drug-related toxicity in this strain.

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