Experimental Animals 

About: Experimental Animals is an academic journal published by Japanese Association for Laboratory Animal Science. The journal publishes majorly in the area(s): Gene & Diabetes mellitus. It has an ISSN identifier of 1341-1357. Over the lifetime, 1926 publications have been published receiving 22245 citations.

Effect of three types of mixed anesthetic agents alternate to ketamine in mice.

Abstract: Ketamine is usually used for murine anesthesia in animal experiments with other anesthetics for its sedation and analgesic effects However, ketamine was categorized as a narcotic drug in Japan on January 1, 2007 After this act came into effect, a narcotic handling license became necessary for using and possessing ketamine Pentobarbital sodium, which is also used for laboratory animal experiments as Nembutal, is no longer being manufactured For these reasons, other anesthetic agents that can be used without a license are needed In this paper, we examined the use of anesthetics other than ketamine and pentobarbital sodium A combination anesthetic (M/M/B: 03/4/5) was prepared with 03 mg/kg of medetomidine, 40 mg/kg of midazolam, and 50 mg/kg of butorphanol The anesthetics were administered to male ICR mice by intraperitoneal injection In order to assess anesthetic depth and duration, we stimulated the mice directly after loss of righting reflexes to recovery of these same reflexes and then recorded four parameters--a tail pinch reflex, a pedal withdrawal reflex in the forelimbs, a pedal withdrawal reflex in the hindlimbs, and corneal reflex Each parameter was scored, and the anesthetic depth, expressed by the total score, was summed The surgical anesthesia duration of M/M/B: 03/4/5 mg/kg was almost identical to the surgical anesthetic duration with a ketamine and xylazine mixture (80-8 mg/kg) These data suggested that mice can be anesthetized by M/M/B: 03/4/5 as an alternate to ketamine We thus can recommend M/M/B: 03/4/5 for murine surgical anesthesia

Genetic differences among C57BL/6 substrains.

Abstract: The C57BL/6 mouse is the most well-known inbred mouse strain, and has been widely used as a genetic background for congenic and mutant mice. A number of C57BL/6 substrains have been derived from the C57BL/6 founder line and are reported to differ in several phenotypes. There are several major sources of C57BL/6 substrains for the biomedical research community. The importance of their genetic and phenotypic differences among substrains, however, has not yet been well recognized by biomedical researchers. Here, we report the result of screening of the functional deletion of the nicotinamide nucleotide transhydrogenase (Nnt) gene and 1,446 SNPs genotyping among seven C57BL/6 substrains from different sources, such as C57BL/6J, C57BL/6JJcl, C57BL/6JJmsSlc, C57BL/6NJcl, C57BL/6NCrlCrlj, C57BL/6NTac, and C57BL/6CrSlc. The deletion of exon 7-11 in the Nnt gene that was previously reported in C57BL/6J was also observed in other C57BL/6J substrains, indicating that this functional deletion probably occurred at an early stage in the establishment of C57BL/6J substrains. The genotyping of SNP loci clearly demonstrate genetic differences between C57BL/6J and C57BL/6N substrains at 11 loci. Besides, we found another SNP differing between C57BL/6J and other C57BL/6J substrains available from commercial breeders. No genetic difference was detected among C57BL/6N substrains. The C57BL/6CrSlc mouse, originally derived from the National Cancer Institute of the NIH was found to be the same as the C57BL/6N substrains by the SNP pattern. These data will be useful for accurate genetic monitoring of genetically engineered mice with the C57BL/6 background.

Changes in colonic mucosal permeability in mouse colitis induced with dextran sulfate sodium.

Abstract: In this study we examined changes in colonic mucosal permeability induced by dextran sulfate sodium (DSS) during the acute phase of mouse colitis. To induce colitis, the mice were given drinking water containing 5% (w/v) DSS (MW=40,000) ad libitum. Colonic mucosal permeability was evaluated by the permeation of Evans blue (EB) from the lumen into the wall of the colon on 1, 2, 3 and 7 days postadministration of DSS. Mucosal changes were also histologically examined daily for 7 days postadministration. The permeation of EB increased significantly by days 3 and 7 postadministration. Histological analysis showed that crypt loss was the initial change, with no inflammatory process and the surface mucosal epithelial cells remained morphologically intact. These histological changes developed on 2 to 3 days postadministration. Erosion was first recognized at 5 days postadministration. These findings indicated that the increase in colonic mucosal permeability may have occurred in 3 days postadministration, and the increase in mucosal permeability occurred before the appearance of the inflammatory process. This suggests that an increase in colonic mucosal permeability, leading to the destruction of mucosal barrier function, may play an important role in the induction of DSS-induced murine colitis.

Derivation of Pluripotential Embryonic Stem Cells from Murine Primordial Germ Cells in Culture.

Abstract: Despite the importance of germ cells to the survival of species, little is known about their embryological origin, proliferation, migration and entry into mitotic arrest or meiosis. We have studied the effect of Steel factor (c-kit ligand), LIF (leukemia inhibitory factor) and bFGF on cultured murine primordial germ cells (PGCs) . We have found that Steel factor and LIF synergistically promote the proliferation of PGCs. However, under these conditions, PGCs have a finite proliferative capacity that correlates with their cessation of division in vivo. In the presence of bFGF, LIF and membrane associated Steel factor but not soluble Steel factor, PGCs continue to grow over the finite proliferative capacity and give rise to colonies of cells resembling undiffer-entiated embryonic stem (ES) cells which can be subcultured. The PGC derived cell lines are indeed pluripotential and can give rise to chimeras when they are introduced into blastocysts. The long term culture of PGCs and the derivation of ES cells from them have implications for germ cell biology, the induction of teratocarcinoma and transgenic technology.

Dextran Sodium Sulfate-Induced Colitis in Germ-Free IQI/Jic Mice

Abstract: This study presents a histological examination of dextran sodium sulfate (DSS)-induced colitis in germ-free (GF) mice. A comparison of the pathology between GF and conventionalized mice (CVz) was made to determine the role that intestinal microflora play in DSS-induced colitis. To induce colitis, GF and CVz IQI/Jic mice were given either 5% or 1% DSS orally. Administration of 5% DSS, a common concentration used to induce colitis in mice, caused gross rectal bleeding and a marked decrease in hematocrit as early as day one in GF mice. These mice died on day three due to massive bleeding into the intestinal lumen. In contrast, CVz mice did not die during the seven-day experimental period. Histopathological examination three days after administration of 5% DSS did not reveal any colitis lesions in GF mice, but CVz mice had developed moderate colitis in the large intestine. Administration of a low concentration of DSS (1%), which only induces mild basal crypt loss in CVz mice, caused severe colitis in the distal colon in GF mice, and they died on day 14. These data suggest that intestinal microflora are not necessary for the induction of colitis. Furthermore, DSS may be highly toxic to GF mice, and when given at a concentration of 5% it causes massive bleeding into the intestinal lumen resulting in death prior to development of colitis.