Charles River Laboratories Japan produces laboratory animals, mainly mice and rats. In its history, we have experienced many crises such as mass food poisoning of staff and contamination of animals. However, we overcame these crises, accomplishing our corporate missions to secure steady supply of healthy animals. Under such circumstances, in 2008, we faced an unprecedented crisis involving a novel influenza possibly becoming pandemic. Therefore, we prepared a Crisis Management Plan (CMP) and Business Continuity Plan (BCP) to avoid the worst case scenario. Fortunately, the novel influenza did not develop into a pandemic and no major problems occurred in production of our laboratory animals. In March 2011, our Tsukuba Breeding Center was struck by the Great East Japan Earthquake. Many cages fell from racks, and consequently, 14,000 mice and rats were euthanized. Moreover, this animal production facility experienced not only blackouts and water outage but also various maintenance problems. After triage of the animals, almost half of the animals kept were eventually lost. However, we recovered and resumed shipment of animals two weeks after the disaster by utilizing the CMP and BCP we initially created as a countermeasure against novel influenza. After two months, our production volume returned to normal except for two strains. I sincerely hope this review, which highlights our experience and related issues, will be a useful resource in regard to crisis management for people who are engaged in laboratory animal care and use.

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In mammals, the vomeronasal system (VS) originating from the vomeronasal organ (VNO; also called “Jacobson’s organ”) is considered to be a chemosensory system that recognizes “pheromone” signals. In the accessory olfactory bulb (AOB), the primary center of the VS, the glomerular cell layer (GL) of the AOB is regarded as an important functional area in the transmission of pheromone signals from vomeronasal sensory neurons (VSNs) of the VNO. In mice, the most frequently used animal model for the study of the VS, the GL of the AOB has several unique histological properties when compared with the main olfactory bulb (MOB): (i) each glomerular size is far smaller than in the MOB; (ii) many juxtaglomerular cells (JGCs) are GABA immunopositive, but subpopulations of cells distributed in the AOB are tyrosine hydroxylase- or calcium-binding protein immunopositive; and (iii) the dendritic branching pattern of the JGC in the AOB is heteromeric. The biological significance of the mammalian VS is still debated. The unique histological properties of the mouse AOB summerized in the present review may give some useful information that may help in understanding the function of the mammalian VS.

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Breeding of fancy mice has been a tradition in Japan. Recent progress in animal science has shed a new light on Japanese wild-derived mice as tools for discovery of new disease models because these mice, Mus musculus molossinus, are genetically far remote from the majority of available laboratory mice. After decades of effort, five inbred strains of mice have been established from pairs of wild mice trapped in Tohoku, northeastern Japan, namely KOR1/Stm, KOR5/Stm, KOR7/Stm, AIZ/Stm, and MAE/Stm. They carried numerous mutations, leading to a variety of diseases. During the inbreeding of KOR1, the first spontaneous mutation was found in the Apoe (apolipoprotein E) gene, and the mutant was later designated as spontaneous hyperlipidemic (SHL). Thereafter, a number of other mutations were discovered among wild-derived inbred strains, including atopic dermatitis, microphthalmia, dominant white spots, sebaceous gland abnormalities, and audible song-like vocalization. Furthermore, to examine the possible effects of the genetic background for these mutant genes, sets of congenic strains were generated, in which the mutant gene was introduced into at least 3 different strains of laboratory mice, including BALB/c and C57BL/6. These congenic strains have now been established as novel disease models. These wild-derived inbred strains serve as a treasure trove for novel disease models. Most of them have been deposited in the Riken BioResource Center (BRC), and some are also available from commercial breeders.

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We isolated a novel murine norovirus (MNV), MT30-2 strain, from feces of conventional mice in Japan to evaluate the virucidal activity of four antiseptics. The MNV MT30-2 strain was inactivated by as little as 0.2% (w/v) povidone-iodine (PVP-I) and 0.1% (w/v) sodium hypochlorite (NaOCl) treatment as determined by a novel plaque assay. Importantly, PVP-I reduced the MNV titer by 4 log₁₀ within 15 s of exposure. The other two antiseptics, benzethonium chloride (BEC) and chlorhexidine gluconate (CHG), did not reduce the MNV titer even when treatment lasted for 60 s. When the virus titer was reduced by PVP-I or NaOCl treatment, the amount of MNV RNA was not reduced, indicating that the presence of viral RNA was not related to the virucidal activity of the antiseptics. PVP-I and NaOCl will be useful in controlling the spread of MNV, which is a common problem in mice colonies. In this study, we isolated a novel MNV and newly revealed that two antiseptics (PVP-I and NaOCl) were able to inactivate MNV at low concentrations and in a short contact time.

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The aim of this study was to establish a lens epithelial cell (LEC) line originated from a cataract of a dog. An anterior capsulorhexis specimen from a dog naturally developing mature cataracts was obtained prior to routine phacoemulsification cataract extraction. The primary lens epithelial cells were transfected with expression plasmid DNA encoding the large T antigen of replication origin-defective simian virus 40 (SV40), and then a colony was cloned using a glass cylinder. The primary cells stopped proliferation in three passages, while the transfected cells remained proliferative. Functional analysis of Na-dependent vitamin C transporter (SVCT) indicated that the Km value toward ascorbic acid (vitamin C) was 19.9 ± 2.8 μM, and RT-PCR analysis showed that SVCT2 was observed in this cell line while SVCT1 was not, which is one of the characteristics of LECs. Western blot analysis and cytoimmunochemistry indicated immortalized cells produced a protein with a molecular mass of 25 kDa, which reacted with an antibody to αB-crystallin within the whole cytosol. The cloned cell line, termed cdLEC, grew well and could be propagated over 250 times by basically splitting at 1:20. These results indicate that cdLEC may also provide a useful in vitro system for the study of the pathophysiology of cataract.

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Many models of diabetic nephropathy have been reported. However, it is rare that the characteristic findings of severe human diabetic nephropathy, such as diffuse, nodular, and exudative lesions, are all detected in one model mouse. Previously, we reported that MAFA-deficient and beta cell-specific MAFK-overexpressing hybrid transgenic (Mafa^–/–Mafk ⁺) mice develop diabetes mellitus and, after uninephrectomy, demonstrate these characteristic lesions. In this study, we administered TCV-116 (candesartan cilexetil) to Mafa^–/–Mafk ⁺ mice after uninephrectomy and examined whether TCV-116 ameliorated the diabetic nephropathy. We also evaluated the utility of these mice as a model for developing treatments for diabetic nephropathy. We performed uninephrectomy of the Mafa^–/–Mafk ⁺ mice at 8 weeks old. We then divided these mice into two groups as follows: 1) an untreated group and 2) a group treated with TCV-116 at 5 μg/g/day from 10 to 20 weeks. TCV-116 treatment did not affect serum glucose levels. However, in the treated group, urinary protein excretion, mesangial matrix expansion, enlargement of the kidney, and glomerular surface area were all improved relative to untreated mice. Oxidative stress is known to be increased in diabetic nephropathy and to be suppressed by TCV-116. The urinary level of 8-OHdG, an oxidative stress marker, at 20 weeks was lower in the TCV-116-treated group than in the untreated group. From these results, we concluded that the Mafa^–/–Mafk ⁺ mouse is a useful model to analyze diabetic nephropathy and a useful tool for the development of new drugs to treat diabetic nephropathy.

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The incidence of spontaneous osteoarthritis (OA) in female STR/Ort mice is much lower than that observed in male STR/Ort mice; however, the reason for the differential incidence of OA between sexes has not been elucidated. Here, we investigated and compared age- and sex-related bone mineral density and architectural changes in male and female STR/Ort mice. Bone architecture and bone mineral density (BMD) of femurs were examined in 5-, 10-, 15-, 20-, and 35-week-old male and female STR/Ort mice by microscopic computed tomography (μCT). Angular degrees of internal tibial torsion (ADITT) were also measured in mice at 5, 15, and 35 weeks of age. Earlier decreases of cancellous volume and BMD were found in male STR/Ort mice. Using μCT, an age-related decline of bone marrow space in femoral diaphysis was observed in both males and females but was more dramatic in females. In addition, an earlier increase of ADITT was observed in male STR/Ort mice, suggesting that internal rotation of the tibia may contribute to OA. Age- and sex-related bone architectural changes clearly differ between male and female STR/Ort mice. These differences in bone structure, particularly ADITT, may explain the differential incidence of OA in STR/Ort mice.

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Whey acidic protein (WAP) has been identified as a major whey protein in milk of a wide range of species and reportedly plays important roles in regulating the proliferation of mammary epithelial cells. However, in some species including humans, WAP is not synthesized in the mammary gland. The presence of WAP in carnivore species has not been reported. We searched the National Center for Biotechnology Information (NCBI) database for the dog WAP gene and tried biochemically to identify WAP in dog milk. The nucleotide sequence of the examined dog genomic DNA was completely identical to that in the NCBI database and showed that the dog WAP gene, like other known functional WAP genes, has four exons. Biochemical analysis of milk protein by reverse-phase HPLC and Western blotting demonstrated the presence of WAP in dog milk.

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This study was conducted to evaluate the oral absorption of enrofloxacin (ENFX) in rats when administered with orange oil or its main component, limonene. Compared with the group administered ENFX alone, the ENFX + limonene group did not show any significant difference in the absorption of ENFX, whereas the extent and rate of absorption of ENFX were significantly decreased in the ENFX + orange oil group (C_max, —43%; T_max, 129%). In addition, t_1/2λz and MRT of ENFX were prolonged by the concomitant administration of orange oil. The AUCs of ENFX were not affected in the ENFX + orange oil group. These results suggest that decreased oral absorption could reduce the efficacy of ENFX therapy in animals.

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