SAMP1/YitFcs mice develop a spontaneous ileitis that resembles human Crohn's disease. This strain may also be useful for the study of inflammatory bowel disease (IBD).
Marcia J McDuffie, University of Virginia Dept of Medicine
These SAMP1 mice have significant breeding difficulties. Please see the JAXMice Health & Husbandry section for the SAMP1 mice Colony Maintenance / Breeding & Husbandry description.
SAMP1/YitFcs (also called SAMP1/YitFc or SAMP1/Fc) mice develop a spontaneous ileitis that is similar in many features to human Crohn's disease. Development of ileitis is accelerated by the presence of luminal bacteria and is characterized by discontinuous segmental inflammation involving the ileum while sparing the proximal small intestine and colon. The histopathologic features of SAMP1/Fc ileitis include transmural inflammation, crypt abscesses, and epithelial changes including loss of villi, crypt elongation, and crypt branching. SAMP1/Fc mice were originally distinguished from the strain from which they were derived (SAMP1/Yit) by spontaneous onset of ileum inflammation by 10 weeks of age at nearly 100% penetrance and the emergence of a perianal fistulizing disease not reported in the parental strain. Other distinguishing characteristics of the SAMP1/Fc substrain include incidence of skin lesions inversely correlated with the occurrence of intestinal inflammation, chronic ileitis with prominent muscular hypertrophy and focal collagen deposition in inflamed segments, activation of mesenteric lymph node lymphocytes coincident with ileitis progression, and high interferon-γ production preceding ileitis onset. Like other spontaneous models of inflammatory bowel disease, SAMP1/Fc mice maintained at higher health status/germ-free conditions may exhibit attenuated ileitis onset and severity compared to SAMP1/Fc mice maintained in lower health status/specific pathogen-free vivaria.
SAMP1/YitFcJ inbred mice have significant breeding difficulties. Please see the strain Breeding Considerations (Maintenance) section for more information on breeding this mouse line.
Siblings from a litter of AKR/J inbred mice (from The Jackson Laboratory; Stock No. 000648) were inadvertently outcrossed to an unknown mouse, and then bred together for more than 20 generations to generate a series of senescence prone strains. One of these senescence accelerated mice (SAM) strains, SAMP1, was identified with shortened life span and early signs of senescence (spontaneous amyloidosis, alopecia, and osteoporosis) by Dr. T Takeda (Kyoto University, Kyoto, Japan). SAMP1 mice were then sent to Dr. S Matsumoto (Yakult Central Institute for Microbiological Research, Tokyo, Japan), where mice showing spontaneous skin ulceration were selectively mated together. During a transfer from a conventional to specific pathogen free vivaria, mice lost the early senescence (amyloidosis) and developed a transmural, discontinuous ileitis and mild hepatic inflammation without necrosis. After more than 20 generations of inbreeding, the resulting SAMP1/Yit mice were established. In 1996, SAMP1/Yit mice were then sent to Dr. Fabio Cominelli (University of Virginia School of Medicine, Charlottesville Virginia, USA) where they were bred together for more than 20 generations. The resulting SAMP1/YitFcs mice (originally called SAMP1/YitFc or SAMP1/Fc) retained the high prevalence of spontaneous ileitis but also show unique characteristics compared with the original Japanese strain; incidence of skin lesions inversely correlated with the occurrence of intestinal inflammation, established ileitis as early as 10 weeks of age, chronic ileitis with prominent muscular hypertrophy and focal collagen deposition in inflamed segments, activation of mesenteric lymph node lymphocytes coincident with ileitis progression, high interferon-γ production preceding ileitis onset, and emergence of perianal disease with ulceration and fistulae. SAMP1/YitFcs mice are H-2k; reported to have the entire MHC region on chromosome 17 identical to that of AKR/J mice. In 2009, SAMP1/YitFcs mice were sent from the University of Virginia School of Medicine to The Jackson Laboratory and assigned the strain name SAMP1/YitFcsJ.
|Allele Name||multiple drug sensitive|
|Allele Synonym(s)||mdr1a-; mdr-3|
|Gene Symbol and Name||Abcb1a, ATP-binding cassette, sub-family B (MDR/TAP), member 1A|
|Strain of Origin||CF-1|
|Molecular Note||The analysis of the genomic locus revealed an insertion of a solo long terminal repeat (LTR) of the ecotropic murine leukemia virus in the reverse orientation in the intron of the mdr-3 gene, causing abnormal splicing and thereby disrupting the mdr-3 gene function. This allele is also present in strains SAMP1, SAMP6, SAMP7, SAMP9, SAMR1, SAMR4 and SAMR5. The identical mutation is found in Crl:CF1 mice.|
When maintaining a live colony, SAMP1/YitFcJ inbred mice are bred together. These inbred mice have significant breeding difficulties. The donating investigator reports:
--it is best to maintain the colony in trio-matings
--approximately 33% of trio-matings are nonproductive
--approximately 33% of trio-matings will only produce one litter
--productive matings produce approximately 2 litters total with an average of 4.8 mice per wean
--if females are not pregnant by 6 weeks of breeding, that female is unlikely to produce any litters
--the donating investigator does not set up mating pens until the mice are at least eight weeks old: even with this delayed mating, litters may not be observed for a few months
--seasonal breeding slumps starting in January may further diminish colony breeding success.
The Jackson Laboratory maintains via trio matings rotation of less than 6 months, and our breeding performance is listed below [as of February 2021]:
--How long for the first litter to be born: 6-9 weeks
--Typical number of litters per breeding female (for average rotation period of time): 3
--Typical number of pups per individual litter: 6
--Non-productive breeders: medium frequency (2–4 matings out of 10)
--Pre-wean loss: low frequency (less than 10% loss)
When using the SAMP1/Fc mouse strain in a publication, please include JAX stock #009355 in your Materials and Methods section.