Refined histopathologic scoring system improves power to detect colitis QTL in mice
Institute for Cellular and Molecular Pathology, Hannover Medical School, Hanover, Lower Saxony, Germany Mammalian Genome
(Impact Factor: 3.07).
12/2004; 15(11):865-71. DOI: 10.1007/s00335-004-2392-2
Induction of colitis in mice by a targeted mutation in the I110 gene is inbred strain dependent. C3H/ HeJBir (C3H) mice are colitis susceptible while C57BL/6J (B6) mice are resistant. Identification of quantitative trait loci (QTL) determining the differential strain responsiveness requires histopathologic scoring of multiple lesion subphenotypes in both cecum and colon. Here we show that ability to detect a major C3H-derived QTL on Chr 3 (cytokine deficiency-induced colitis susceptibility 1, Cdcs1) was critically dependent upon the degree of refinement of the histopathologic scoring system. QTL mapping was performed using a first-back-cross population of interleukin-10-deficient mice and applying two different grading systems to assess lesion subphenotypes. The same histological specimens were scored by two independent pathologists using either a very detailed scoring system for four subphenotypes developed at The Jackson Laboratory (TJL) or a simpler scoring system developed at the Hannover Medical School (MHH). The more detailed TJL subphenotyping protocol increased power to identify Cdcs1 (a maximum LOD score of 4.28 versus a LOD score of 1.77 when using the abbreviated MHH subphenotyping scoring system). This study shows that for QTL mapping in a mouse model of colitis, in which histology represents the gold standard for phenotyping, ability to detect linkage is critically dependent upon the degree of refinement adopted for separately scoring the multiple histopathologic lesions comprising this complex phenotype.
Available from: Robert Laudeley
- "The cecum and colon were fixed in 4% formaldehyde, embedded in paraffin, cut into 4–6 µm sections, and stained with hematoxylin and eosin. Histological scoring was done in a blinded fashion and followed a scheme adapted from Cooper et al.
 and Bleich et al.
, including the following criteria: epithelial changes (crypts unchanged: 0, loss of basal ⅓: 1, basal ⅔: 2, complete: 3, loss of crypts plus ulceration: 4), cellular infiltration (none: 0, infiltrates in lamina propria: 1, in lamina propria plus edema formation: 2, in lamina propria and submucosa: 3), area involved (none: 0, 10–30%: 1, 40–60%: 2, >60%: 3; applied to each of the parameters). This scheme yielded scores from 0–13 for each segment (cecum; proximal, medial, and distal colon), i.e. 0–39 for total colon and 0–52 for colon plus cecum. "
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ABSTRACT: Inflammatory bowel diseases are a critical public health issue, and as treatment options remain limited, there is a need to unravel the underlying pathomechanisms in order to identify new therapeutic targets. Complement activation was found in patients suffering from inflammatory bowel disease, and the complement anaphylatoxin C5a and its receptor C5aR have been implicated in disease pathogenesis in animal models of bowel inflammation. To further characterize complement-related pathomechanisms in inflammatory bowel disease, we have investigated the role of the anaphylatoxin C3a receptor in acute dextran sulfate sodium-induced colitis in mice. For this, colitis was induced in C3a receptor-deficient BALB/c and C57BL/6 mice, and disease severity was evaluated by clinical and histological examination, and by measuring the mRNA expression or protein levels of inflammatory mediators in the tissue. C3a receptor deficiency was partially protective in BALB/c mice, which had significantly reduced weight loss, clinical and histological scores, colon shortening, and CXCL-1/KC mRNA, myeloperoxidase and interleukin-6 tissue levels compared to the corresponding wild type mice. In C57BL/6 mice the differences between wild type and C3a receptor-deficient animals were much smaller and reached no significance. Our data demonstrate that the contribution of C3a receptor to disease pathogenesis and severity of dextran sulfate sodium-induced colitis in mice depends on the genetic background. Further studies will be required to clarify whether targeting of C3a receptor, possibly in combination with C5a receptor, might be considered as a therapeutic strategy for inflammatory bowel disease.
Available from: Myriam Martin
- "Small intestine, caecum and colon were removed and the length of the colon from the colocaecal junction to the anus was measured. The small intestine was divided in two equal parts, and both parts as well as the colon were prepared as a 'Swiss Roll' (Moolenbeek & Ruitenberg 1981) without being opened before rolling, the caecum was bisected with a razor blade after overnight fixation (Bleich et al. 2004). All parts were processed routinely for histological examination , and stained with haematoxylin and eosin. "
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ABSTRACT: Mongolian gerbils are used as biomedical research models for a variety of diseases and are in some cases suited better than other rodents for basic research and therapeutic studies. The aim of this study was to establish and characterize a dextran sulphate sodium (DSS)-induced model in gerbils for the human inflammatory bowel disease (IBD) and to utilize them for a therapeutic study in vivo. Four concentrations (0.5%, 1%, 2% and 4%) of DSS were administered via drinking water for 7 days; based on these results, a concentration of 3% DSS was given for 9 days in a second approach. Fluid uptake and general clinical condition were assessed daily using a clinical score. Caecum and colon were scored histologically. Fluid uptake was affected by addition of DSS to the drinking water. First clinical symptoms were observed at day 4 of DSS treatment with a considerable increase in clinical score parameters only in gerbils receiving 2% or 4% DSS. Histologically, ulceration and inflammation were observed predominantly in the caecum of gerbils treated with at least 1% DSS; reproducible inflammation in the colon required at least 2% DSS. Using 3% DSS for 9 days, considerably more inflammation was induced in the colon, comparable with lesions usually observed in the mouse model. Using an optimized protocol, DSS treatment induces reproducibly typhlocolitis in Mongolian gerbils, rendering them as a useful model for IBD.
Available from: Jose M Bruno-Barcena
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