Atopic dermatitis (AD) is a chronic inflammatory skin disease, with its major clinical feature being persistent itch sensation in the skin. There are extremely few animal models to reproduce the complicated condition of a patient with AD; therefore researchers have been confronted with some difficulties in pathologic analysis and drug development for AD. Although various models have been proposed and developed, there is no doubt that the spontaneous mouse model, NC mice, gave the greatest impact. NC mice enabled us to analyze pathogenesis of allergic skin abnormalities as well as development of new drugs for AD. However, many questions still remain in the pathogenesis of AD. In recent years, the study of the itch has attracted our attention because itch is one of the most unbearable symptoms of AD. For development of an effective treatment to overcome the itch, not only a precise animal model but also an accurate evaluation protocol are needed. This review summarizes some mouse models of AD, particularly focusing on NC mice, together with a novel evaluation system for scratching behavior of mice to help the understanding of researchers.
Hearing is a major factor in human quality of life. Mouse models are important tools for discovering the genes that are responsible for genetic hearing loss, and these models often allow the processes that regulate the onset of deafness in humans to be analyzed. Thus far, in the study of hearing and deafness, at least 400 mutants with hearing impairments have been identified in laboratory mouse populations. Analysis of through a combination of genetic, morphological, and physiological studies is revealing valuable insights into the ontogenesis, morphogenesis, and function of the mammalian ear. This review discusses the advantages of the mouse models of human hearing impairment and highlights the identification of the molecules required for stereocilia development in the inner ear hair cells by analysis of various mouse mutants.
We determined partial cDNA sequences of four immunoglobulin (Ig) classes—IgM, IgG1, IgE, and IgA—of Mongolian gerbil (Meriones unguiculatus). Each deduced Ig heavy-chain constant (IGHC) region—Cμ, Cγ1, Cε, and Cα—is structurally similar to its counterparts in the mouse and rat, and phylogenetic analysis suggests that the gerbil Igs are evolutionarily close to their counterparts. In spite of the high sequence homology to the other rodent Cγ sequences, the gerbil Cγ1 sequence differs from our previously reported Cγ2. This result indicates that the gerbil has at least two IgG subclasses. These four gerbil IGHC cDNA sequences will be useful for determining gerbil Ig isotypes and examining the expression of gerbil Ig mRNAs in response to parasitic and bacterial infections.
Preferences for different housing conditions in mice were evaluated by radiotelemetry. Male C57BL/6J and ICR mice were used. Preference for bedding materials in mice was compared among three materials, wood shavings (WS), paper (CF) and cloth (AG), using the length of stay in cages as a parameter. The results indicated that mice stayed longer in a cage with AG than in cages with other bedding materials. The present study confirmed our previous results and thereby indicated that radiotelemetry is a useful method to evaluate impacts of housing conditions on animal welfare. In the second part of this study, we used radiotelemetry to evaluate color preference of the mice for cloth bedding material. In C57BL/6J mice, staying time in black cloth was significantly longer than that in white cloth. In ICR mice, staying time in white cloth was significantly longer than that in black cloth. The mice preferred the environment with the same color as their fur, which may be important for animal welfare.
We previously demonstrated the cAMP-PKA pathway to be associated with the reduction in aggregated proteins such as immune complex in glomeruli. The aim of this study was to clarify whether PKC is involved in the reduction of aggregated protein and phosphorylation of CREB in aggregated protein-loaded glomeruli. Mice were injected with aggregated bovine serum albumin (a-BSA), and glomeruli were isolated. The a-BSA-injected mice produced more cyclic AMP and had more phosphorylated serine and phosphorylated CREB in their glomeruli than the controls. The expression of phospho-CREB increased with the accumulation of a-BSA. KT5720 and H7 suppressed the increase in phosphorylated CREB in a-BSA-loaded glomeruli and the decrease in accumulated a-BSA in the glomeruli. These findings suggest that PKC is associated with the reduction of aggregated protein and phosphorylation of CREB in aggregated protein-loaded glomeruli.
The aim of this study was to investigate the synthesis of α2-macroglobulin (α2M) in hepatopathic rats injected with turpentine oil to induce acute inflammation. Hepatopathy was induced by oral administration of acetaminophen at a dose of 1 g/kg daily for 2 weeks or a 25% solution of carbon tetrachloride (CCl4) at 2 ml/kg body weight three times per week for 7 weeks. Acute inflammation was induced by intramuscular injection of turpentine oil at a dose of 1.0 ml/kg body weight. Serum concentrations of α2M were measured by enzyme-linked immunosorbent assay. Aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and total protein differed significantly between acetaminophen or CCl4-induced hepatopathic rats and acetaminophen control (AA-control) or CCl4 control (CC-control) rats. Furthermore, pathological examination confirmed hepatopathy in rat livers. Peak serum concentrations and area under the time-concentration curve for α2M showed significant differences between hepatopathic rats and AA-control or CC-control rats. Thus, serum concentrations of α2M did not increase when compared with nontreated rats.
A-type (atrial) natriuretic peptide (ANP) levels in the heart and plasma were examined by immunohistochemistry, electron microscopy, and radioimmunoassay (RIA) in angiotensin II type 1a receptor knockout (Agtr1a KO) mice. Additionally, the ANP mRNA level in the heart was measured using a real-time polymerase chain reaction (PCR) assay. The blood pressure in Agtr1a KO mice was significantly lower than that in wild-type (WT) mice. The number of ANP granules and ANP immunoreactivity in the auricular cardiocytes were significantly lower in Agtr1a KO mice than in WT mice. Ultrastructurally, the ventricular cardiocytes in Agtr1a KO mice occasionally had ANP-like granules, which were not present in WT mice. The plasma, auricular, and ventricular ANP and plasma cyclic guanosine monophosphate (cGMP) concentrations were significantly higher in Agtr1a KO mice than in WT mice. The ANP mRNA levels of the auricular and ventricular cardiocytes in the Agtr1a KO mice were almost twice as large as those in WT mice. The present data suggest that a notable increase in the ANP biosynthesis and release in the heart of Agtr1a KO mice may account for the reduction in blood pressure together with the lack of an AGTR1A receptor in this model.
Cryopreservation is the long-term storage of viable cells/tissue in liquid nitrogen. The present study was conducted to freeze 8-cell- to morula-stage mouse embryos from the ACTREC Laboratory Animal Facility using a “slow freezing and fast revival” method. In all, 4,088 embryos were collected from 495 donor female mice of ten different strains. An average recovery of 8 embryos per donor mouse were recorded. Of the 4,088 embryos, 3,946 embryos of normal morphology were frozen in 173 straws. They were cooled down using a controlled-rate freezing assembly, and the straws were directly plunged into liquid nitrogen for long-term storage. Out of these 3,946 frozen embryos, 2,650 were found to be viable after fast revival. The highest survival rate, 81%, was recorded in B6D2F1 hybrid mice, whereas the lowest rate, 51%, was recorded in the S/RV/Cri-ba mutant strain. Out of 2,650 viable embryos, 2,359 embryos (89%) developed to the blastocyst stage after 24 h of incubation in a CO2 incubator. The developed blastocysts were transferred surgically into 101 pseudopregnant female mice, of which 49 (48.5%) females were found to be pregnant. The highest percentage of pregnancy, 75%, was recorded in C57BL/6NCrl and NIH-III mice, whereas no pregnant recipients were recorded in Ptch, C3H/HeNCrl and NOD SCID mice. Based on the deliveries of these 49 females, an average of 4 young were delivered per female. Improvement in efficiency of freezing, thawing, and surgical transfer of embryos into pseudopregnant females is one of the challenges in such studies.
We evaluated the utility of animal skins for determining the skin blanching of steroids. A Chroma Meter was used to determine the skin blanching of steroids. Hydrophilic creams containing clobetasol propionate (CP) or prednisolone (PS) were selected as model steroid formulations. Skin blanching, a*, was determined using a Chroma Meter after the application of 0.005, 0.01, 0.1, or 1.0% CP or PS hydrophilic cream to the back skin of guinea pigs and hairless rats for 24 h. The relationships between Δa*6h and the skin concentrations of the steroids were determined at 6 h after removal of the cream. Δa*6h was markedly decreased after the application of CP hydrophilic cream to guinea pigs, and a good linear relationship was observed between Δa*6h and skin concentration (r=0.98). In contrast, no relationship was observed between these parameters after the application of CP cream to the hairless rats. Although skin blanching was observed after PS cream application in guinea pigs, no relationship was observed between Δa*6h and skin concentration of PS in each animal. These results suggest that the skin blanching effect of CP in guinea pigs is greater than that of PS and that its blanching effect in guinea pigs was stronger than that in hairless rats. Guinea pigs were found to be a good animal model for determining the skin blanching produced by steroid creams. In addition, Chroma Meters can be effectively used in skin vasoconstrictive tests in guinea pigs.
Manganese (Mn2+)-enhanced MRI (MEMRI) is known to provide insight into functional and anatomical biology. However, this method, which uses Mn2+ as a MRI-detectable contrast agent, has drawbacks such as the toxicity to cells beyond a certain level of Mn2+. In this study, we attempt to determine a new method of ICV administration, the optimal concentration of administered Mn2+ and the optimal MEMRI acquisition time following administration. Male Sprague-Dawley rats were used in the following experimental sessions: (1) intracerebroventricular (ICV) cannula implantation in the region of the cisterna magna, (2) serial dilution of MnCl2 (20–80 mM), (3) ICV administration of MnCl2 through the cannula, and (4) T1-weighted MRI measurements. We confirmed that cannula implantation in the region of the cisterna magna was a new ICV injection method for the administration of a contrast agent. The optimal concentration for MEMRI was 20/50 mM/μl of MnCl2. The MEMRI data acquired at different time points indicate that most signal enhancement is maintained during 14–48 h after contrast agent injection, and 24 h was the optimal time to acquire images of the rat brain. The present study offers optimized parameters for contrast agent injection that would be a good basis for studies using MEMRI to research the rat brain.
Pentobarbital (PB) and ketamine (Ket) influence the concentration of neurotransmitters in the brain. PB has been reported to decrease the extracellular nitric oxide (NO) concentration through a decrease in acetylcholine (ACh) release, while Ket has been shown to increase the NO concentration via an increase in ACh release. Here, we investigated effects of PB and Ket on NO release and the relationship between NO and ACh in the rat striatum by in vivo microdialysis experiments. Male Sprague-Dawley rats were used. A microdialysis probe was inserted into the right striatum and perfused with modified Ringer’s solution. Samples were collected every 15 min and injected into an HPLC system. The rats were freely moving, and PB and Ket were administered intraperitoneally. Neostigmine (1 and 10 μM) and mecamylamine (100 μM) were added to the perfusate. Calcium and magnesium concentrations were modified for each anesthetic to influence ACh release. PB decreased NO products (NOx) while Ket increased them. While perfusion with neostigmine showed no effect on baseline NOx concentrations, it diminished the PB-induced NOx reduction at low concentrations and abolished it at high concentrations. Magnesium-free perfusion had no effect on baseline NOx concentrations, whereas perfusion at a low magnesium concentration antagonized the PB-induced NOx reduction. Mecamylamine and calcium-free perfusion had no effect on baseline NOx concentrations and Ket-induced NOx increases. PB may decrease NO release through reduction in ACh release, whereas Ket may increase NO release independent of ACh regulation.
The aim of this study was to collect data on immunological parameters from Wistar Hannover rats at 8, 10, 19, and 32 weeks of age. Low leukocyte parameter cell counts, serum globulin concentration, and T, B, and NK lymphocyte counts in peripheral blood at each time point; low T, B, and NK splenocyte counts; and high, or tendencies toward high, thymocyte counts at 10 weeks of age were noted in females when compared with males. KLH-specific antibody production increased gradually with age in both sexes. The immunological data noted for leukocyte parameters, the serum globulin concentration, and immunophenotyping (peripheral blood, spleen, and thymus) relating to chronological changes and sex differences may be useful in assessing drug-related immunotoxicity in this strain.
In this study, we found that almost all institutions conducting animal experiments, such as universities, corporations, and research laboratories, also conducted memorial services for the animals sacrificed during animal experimentation. A questionnaire survey was conducted among 120 institutions. A total of 83 (69.1%) valid responses were obtained from the participating institutions. Memorial services were held at 79 institutions (95.1%). Memorial services for laboratory animals have been mainly conducted to show appreciation, comfort the spirit, and console the souls.
We have invented a mouse model of periodontitis associated with alveolar bone loss induced by lipopolysaccharide. Ovariectomized (OVX) animals are widely used as a model for osteoporosis due to estrogen deficiency. To define the relationship between periodontitis and osteoporosis, we examined the influence of estrogen deficiency on the mouse alveolar bone mass. In OVX mice, bone loss was detected not only in the femur, but also in the alveolar bone, indicating that estrogen deficiency could induce resorption in alveolar bone. In experiments using a combination of osteoporosis and periodontitis models, OVX significantly enhanced the alveolar bone loss in the model of periodontitis. Therefore, postmenopausal osteoporosis may enhance the risk of periodontitis associated with inflammatory alveolar bone resorption.