Ubiquitination is required throughout all developmental stages of mammalian spermatogenesis. The two ubiquitin C-terminal hydrolase (UCH) enzymes, UCH-L1 and UCH-L3, deubiquitinate ubiquitin-protein conjugates and control the cellular balance of ubiquitin. These two UCH isozymes have 52% amino acid identity and share significant structural similarity. A new function of these two closely related UCH enzymes during spermatogenesis which is associated with germ cell apoptosis has been analyzed. Apoptosis, in general, is thought to be partly regulated by the ubiquitin-proteasome system. During spermatogenesis, apoptosis controls germ cell numbers and eliminates defective germ cells to facilitate testicular homeostasis. In this paper, I review the distinct function of the two UCH isozymes in the testis of gad and Uchl3 knockout mice, which are strongly but reciprocally expressed during spermatogenesis. In addition, the importance of UCHL1-dependent apoptosis for normal spermatogenesis and sperm quality control is discussed.

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We examined the pharmacokinetic interactions of enrofloxacin and flunixin in male ICR mice that were subcutaneously (SC) administered with both or either one of the drugs. The experiments were performed on the following three groups: flunixin alone (2 mg/kg, SC), combination of flunixin (2 mg/kg, SC) and enrofloxacin (10 mg/kg, SC), and enrofloxacin alone (10 mg/kg, SC). Blood samples were collected at 5, 15 and 30 min, and 1, 2, 3, 4, 5 and 6 h after the drug administration, and the pharmacokinetic parameters of flunixin and enrofloxacin were evaluated from the plasma drug concentrations. Significant changes were detected in the pharmacokinetics of flunixin following its coadministration with enrofloxacin. Coadministration of flunixin and enrofloxacin resulted in a 41% increase of the area under the curve (AUC) and a 53% extension of the terminal half-life of flunixin; moreover, flunixin attained the maximum plasma drug concentration 2.75 times faster than when administered alone. The terminal rate constant and the maximum plasma drug concentration showed significant decreases of 34% and 33%, respectively, following the coadministration of enrofloxacin and flunixin as compared to those following the administration of flunixin alone. In contrast, no significant difference in the pharmacokinetics of enrofloxacin was detected following its coadministration with flunixin, as compared to those following the administration of enrofloxacin alone. Following the administration of enrofloxacin alone or its coadministration with flunixin, the plasma level of ciprofloxacin, the metabolite of enrofloxacin, was very low or undetectable. In conclusion, the pharmacokinetics of flunixin in ICR mice are altered by the coadministration of flunixin and enrofloxacin.

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Corynebacterium (C) kutscheri and Staphylococcus aureus were isolated from two Sprague-Dawley (SD) rats with a hemisected spinal cord. Grossly, gray-white bulging foci and abscesses were distributed throughout the parenchyma of the lung. Pathologically, severe necrotizing lobar pneumonia with abscesses and fibrinous pleuritis were observed. Immunohistochemical analysis found accumulation of galectin-3 in alveolar macrophages and the alveolar interstitial region. No other viral or bacterial pathogens were detected in these animals. In addition, similar pathogenic changes and accumulation of galectin-3 were observed in the lungs of SD rats experimentally infected with C. kutscheri. Using northern blot analysis, the relative galectin-3 and GAPDH mRNA levels were 4.6 to 9.3 times higher in C. kutscheri-infected lung than in uninfected controls. These results demonstrate that a single C. kutscheri infection can induce the upregulation of galectin-3 in the lung and that this molecule may have an important pathogenic role in C. kutscheri infections in rats.

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We previously identified mutant alleles of the lanosterol synthase (Lss) and farnesyl diphosphate farnesyl transferase 1 (Fdft1) genes, which function in the cholesterol biosynthesis pathway, as determinants for hereditary cataracts in the SCR rat strain. Lss^S and Fdft1^S were established as hypomorphic alleles with missense nucleotide substitutions, while Lss^l is a null allele with nucleotide deletion/insertion mutations. Here we report a more detailed characterization of the rat Lss and Fdft1 genes. Screening of various laboratory rat strains revealed that the hypomorphic Lss^S and Fdft1^S alleles are not specific to the SCR strain, but are widely prevalent in other laboratory rat strains. Meanwhile, Lss^l was not found in any rat strains examined. It was also found that functional inter-strain polymorphisms are present in the Lss upstream regulatory region. The BN strain had a higher potential for expression of Lss transcripts than ACI and SCR under conditions where cholesterol synthesis is necessary. SCR was less efficient than BN and ACI in suppressing Lss transcription in circumstances when cholesterol synthesis should be halted. These findings not only imply that there is a genetic polymorphism for cholesterol homeostasis in laboratory rats, but also point to the possibility that rat strains with different Lss alleles exhibit different responses to measures intervening in cholesterol metabolism.

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Hypophysectomy (HX) arrests bone growth and induces osteopenia in the long bones of rats. The present study investigated the combined effect of vitamin K₂ and risedronate on long bone mass in HX rats, in order to determine whether treatment with these two agents had an additive effect. Forty female Sprague-Dawley rats were hypophysectomized at 6 weeks of age by the supplier, and were shipped to our laboratory at three days after surgery along with ten intact rats that served as age-matched controls. The study was started on the day when the rats were received. Three HX rats were excluded from the study because of the failure of HX. Forty-seven rats (6 weeks old) were assigned to the following 5 groups by the stratified weight randomization method: intact controls, HX alone, HX + vitamin K₂ (30 mg/kg, p.o., daily), HX + risedronate (2.5 μg/kg, s.c., 5 days a week), and HX + vitamin K₂ + risedronate. The dosing period was 4 weeks. HX resulted in a decrease of the femoral bone area, bone mineral content (BMC) and bone mineral density (BMD), as well as a decrease in the cancellous bone mass of the proximal tibial metaphysis and the total tissue and cortical areas of the tibial diaphysis. These changes were associated with a marked reduction in the serum level of insulin like growth factor (IGF)-I and with elevation of serum alkaline phosphatase (ALP) and pyridinoline. Administration of vitamin K₂ increased the serum ALP level in HX rats, but did not affect any of the other parameters. On the other hand, risedronate ameliorated the decrease of femoral BMD and cancellous bone mass at the proximal tibial metaphysis in HX rats without affecting the serum IGF-I level, as a result of not causing a significant elevation of serum pyridinoline. Vitamin K₂ and risedronate combined had an additive effect on the femoral bone area, BMC and BMD, and the combined treatment group did not show any significant reduction of the total tissue and cortical areas at the tibial diaphysis, as well as a reduced serum pyridinoline level compared with untreated rats and an increased serum ALP level compared with untreated or risedronate-treated rats. These results suggest that risedronate had a positive effect on the BMD and cancellous bone mass of long bones in HX rats. Despite the lack of a significant effect of vitamin K₂ on bone mass parameters, it had an additive effect with risedronate on the BMC, BMD and cortical bone mass of long bones in HX rats.

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Objective: To explore a method of establishing a rabbit model of superior vena cava obstruction (SVCO) by injecting VX2 tumor cell suspension transcutaneously under ultrasound guidance. Methods: A suspension of VX2 tumor cells was prepared under sterile conditions. Fifteen adult healthy New Zealand White rabbits were enrolled in the experiment. Under ultrasound guidance, about 0.1 ml of the living tumor cell suspension was transcutaneously injected in front of the anterior wall of the right superior vena cava (SVC). The lumen, wall, blood flow of SVCs and adjacent tissues were examined with gray-scale and color Doppler ultrasonography, every 3 days starting from the 9th day after injection. Meanwhile, CT scanning and digital subtraction angiography (DSA) were also performed. The rabbits were dissected immediately after death and tissue samples were collected for pathologic examination. Results: Fourteen out of 15 rabbits developed tumors that were located close to SVCs and/or SVCs cavity, which was shown by ultrasonography. The diameters of the tumors were 80.7 ± 4.3 mm. These tumors grew close to SVCs area and resulted in compression and infiltration of SVCs. CT scanning and DSA confirmed the establishment of the SVCO model. The achievement rate of the SVCO model was 93.3%. No rabbit died of complications. Conclusion: A method of establishing a rabbit SVCO model by injecting VX2 tumor cell suspension under ultrasonographic guidance was established successfully, and it proved to be simple, effective and repeatable. The imaging characteristics of this model are in good accordance with those of SVCO in patients.

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Repeated treatment with methamphetamine (METH) causes long-term behavioral changes, so-called behavioral sensitization (BS), in humans as well as experimental animals. However, there are no reports as to whether repeated METH treatment can establish BS in stress-sensitive Long-Evans (LE) rats. Thus, we investigated the effect of repeated METH treatment (5 mg/kg × 5 days) on the establishment of BS in LE rats. Wistar (WIS) rats were used as a reference. In LE rats, repeated METH treatment failed to cause BS although it did enhance METH-induced hyperlocomotion in WIS rats. The levels of METH in brain dialysate and the ratio of the area under the concentration-time curve area in plasma to that in brain dialysate was increased in repeated METH-treated WIS rats as reported previously, but not in repeated METH-treated LE rats. METH increases plasma corticosterone (CORT) in both strains. However, the intensity of increment of CORT by repeated METH was lower in LE rats than that in WIS rats. Repeated METH treatment decreased the expression of METH-transposable and CORT-sensitive transporter, organic cation transporter 3 (OCT3), in the brain of WIS rats. However, the intensity of the decrement of OCT3 with repeated METH treatment was similar between both strains. Taken together, these results suggest that the lack of establishment of BS in LE rats might have been caused by the unchanged brain penetration of METH after repeated METH administration, and that the differential CORT response to METH is an important strain difference.

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NARCOBIT is the first anesthetic system for mice and rats to incorporate a ventilator. Therefore, it is expected to improve the reliability of mice and rat experiments by accurately controlling and maintaining the depth of anesthesia. In this study, we used NARCOBIT for inducing inhalational anesthesia in mice and evaluated the changes in their hemodynamic parameters. ICR mice were anesthetized with 5% isoflurane and room air, followed by endotracheal intubation. Subsequently, they were mechanically ventilated, and anesthesia was maintained by 2% isoflurane for a 60-min period (maintenance state) using NARCOBIT. In study 1, the heart rate (HR) and mean arterial blood pressure (MAP) were measured. The skin blood flow (SBF) from the hind legs was continuously measured during the maintenance state. Subsequently, the concentration-dependent effects of isoflurane on MAP were examined. In study 2, blood samples were obtained from the abdominal aorta for blood gas analysis. The HR and MAP decreased after anesthesia but were stable during the maintenance state. Decreased MAP and concentration-dependent effects of isoflurane were observed. The SBF increased slightly during the maintenance state but this increase was insignificant. The blood gas analysis showed neither hypoxia nor hypercapnia. Since the use of NARCOBIT enables the anesthetic concentration of isoflurane to be easily changed, a suitable anesthesia depth can be obtained for experimental purposes. Therefore, we conclude that NARCOBIT can be used for providing inhalational anesthesia to mice.

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Changes of estrous cycles with aging of F344/N rats between 1 and 30 months of age (M) were monitored by vaginal smear cytology. The vaginal opening and first cornified cell phase were identified at 1.3 ± 0.1 M and 1.5 ± 0.2 M, respectively. Thereafter, estrous cycles showed about 5-day intervals, and ceased at 16.4 ± 1.2 M. Thereafter irregular appearance of single cornified cell phases without the preceding of nucleated cell phases interspersed with a predominant leukocyte phase was seen in vaginal smears until 26.9 ± 0.5 M. Growing and mature follicles as well as corpora lutea persisted until at least 30 M, and characterized the post reproductive aging of F344/N females. The F344/N rats seem to resemble humans in that the cessation of estrous cycles occurs at approximately half their entire lifespan. However, other aging characteristics are unknown in postmenopausal women. Therefore, we must be careful when extrapolating the aging changes of reproduction in F344/N rats to human beings.

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We studied the impact of "IVF - ET" on the glucose tolerance test (GTT), insulin tolerance test (ITT) and adiponectin to investigate differences in the phenotypes of B6J- Irs2^-/- mice. The B6J-Irs2^-/- mice (KO-Nat group) were prepared by natural mating. Other mice were produced by IVF-ET used ICR strain recipients and surrogate mothers (KO-IVF group). Measurement of body weight, GTT, ITT and blood sampling were performed at the ages of 6, 14 and 24 weeks after birth. Body weights, impaired glucose tolerance, insulin resistance and plasma adiponectin concentrations did not differ for each gender between the KO-IVF and KO-Nat groups. Therefore, we concluded that phenotypes of Irs2^-/- mice produced by reproductive technology are stable.

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A 28.5-year-old female Japanese macaque (Macaca fuscata) was euthanatized because of abdominal distension due to severe ascites. Nodular lesions of varying sizes up to 5 mm in diameter were distributed diffusely on the surface of the omentum, mesentery and parietal peritoneum. No neoplastic masses were detected in any visceral organ. The nodules were composed of proliferation of mono- or multi-layered epithelial-like cells occasionally showing papillary growth and sheets of small round or polygonal cells. Signet ring-like cells and tubular structures were occasionally present. Neoplastic cells were strongly positive to cytokeratin, and occasionally to vimentin. Based on gross and histopathological findings, this tumor was diagnosed as an epithelial type of peritoneal malignant mesothelioma, the first reported case in the non-human primates.

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The Spontaneously Epileptic Rat (SER), a double-mutant for tremor and zitter mutations, shows spontaneous occurrences of absence-like and tonic seizures. Several lines of evidence suggest that the combined effect of Aspa and Atrn mutations is the most likely cause of the epileptic phenotype of the SER. To address this issue, we produced a new double-mutant mouse line carrying both homozygous Aspa-knockout and Atrn^mg-3J mutant alleles. The Aspa/Atrn double-mutant mice exhibited absence-like and tonic seizures that were characterized by the appearance of 5-7 Hz spike-wave-like complexes and low voltage fast waves on EEGs. These results demonstrate directly that the simultaneous loss of the Aspa and Atrn gene functions causes epileptic seizures in the mouse and suggest that both Aspa and Atrn deficiencies might be responsible for epileptic seizures in the SER.

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Introducing rabbits as genetic materials into institutes for experimental animals from other colonies is essential for biomedical research. Currently, it is inconvenient to transport live rabbits from abroad, since they suffer from stress, are prone to accidents and must be inspected, as well as endure quarantine during the often long journey. To overcome these limitations of live animals, we transported sperm cryopreserved in liquid nitrogen. Rabbit sperm was collected from complement C6-deficient rabbits in Germany and then transported to Japan using a dry-shipper containing liquid nitrogen. After thawing the frozen semen and artificial insemination (AI), eleven live pups were born. Subsequently, a homozygous C6-deficient rabbit colony was established.

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