Ogiolda L, Wanke R, Rottmann O, Hermanns W, Wolf E
Lehrstuhl für Molekulare Tierzucht und Haustiergenetik/Genzentrum, Ludwig-Maximilians-Universität, München, Germany.
Anat Rec. 1998 Mar;250(3):292-9. doi: 10.1002/(SICI)1097-0185(199803)250:3<292::AID-AR4>3.0.CO;2-2.
Selection for body weight provides important animal models for studying mechanisms of growth regulation. This study evaluated growth responses of the gastrointestinal tract (GIT) to long-term selection of mice for high (H line) or low (L line) 8-week body weight as compared with random-bred controls (C line).
Weights and dimensions of the various parts of the GIT were recorded from 8-month-old mice. For light microscopic stereological analyses, samples were taken from eight equidistant locations covering the whole jejunum/ileum. Vertical sections were used for estimation of fractional volumes of mucosa, submucosa, and muscularis and of villous surface area density and for measurement of villus length.
Differences between groups in weights and dimensions of the various parts of the GIT were more pronounced in the proximal than in the distal segments, with greatest values in H, followed by C and L mice. Relative to body weight, intestinal growth was similar in the three lines, except for significantly (P < 0.001) increased relative weights of jejunum/ ileum, caecum, and colon in L mice. The fractional volume of mucosa and villus length decreased, whereas the fractional volumes of submucosa and muscularis increased from the proximal to the distal locations. The absolute volume of mucosa was greatest in H mice, followed by C and L mice. Relative to body weight, the volume of mucosa was significantly (P < 0.01) greater in L mice than in the two other lines. The mean total villous surface area of jejunum/ileum was significantly (P < 0.01) different among the three lines (L line: 144 cm2; C line: 227 cm2; H line: 304 cm2) but proportionate to differences in metabolic body weight.
Selection for body weight affected various parts of the GIT to a different extent. The parameters investigated changed markedly along the small intestine, demonstrating the need for systematic sampling. Vertical section stereology provides unbiased estimates of total villous surface area, which is a parameter of major biological significance.
对体重进行选择可为研究生长调节机制提供重要的动物模型。本研究评估了胃肠道（GIT）对长期选择的高8周体重（H系）或低8周体重（L系）小鼠的生长反应，并与随机繁殖对照（C系）进行比较。
记录8月龄小鼠GIT各部分的重量和尺寸。对于光学显微镜体视学分析，从覆盖整个空肠/回肠的八个等距位置取样。垂直切片用于估计黏膜、黏膜下层和肌层的分数体积以及绒毛表面积密度，并测量绒毛长度。
GIT各部分的重量和尺寸在组间的差异在近端比远端更明显，H系小鼠的值最大，其次是C系和L系小鼠。相对于体重，除L系小鼠空肠/回肠、盲肠和结肠的相对重量显著增加（P < 0.001）外，三线小鼠的肠道生长相似。从近端到远端位置，黏膜分数体积和绒毛长度降低，而黏膜下层和肌层分数体积增加。H系小鼠的黏膜绝对体积最大，其次是C系和L系小鼠。相对于体重，L系小鼠的黏膜体积显著（P < 0.01）大于其他两系。空肠/回肠的平均总绒毛表面积在三线之间有显著差异（P < 0.01）（L系：144 cm²；C系：227 cm²；H系：304 cm²），但与代谢体重的差异成比例。
对体重的选择对GIT各部分的影响程度不同。所研究的参数沿小肠有显著变化，表明需要进行系统取样。垂直切片体视学可提供对总绒毛表面积的无偏估计，这是一个具有重要生物学意义的参数。
