Miyata Tohru, Minai Yuji, Haga Minoru
Department of Bioresource Science, College of Agriculture, Tamagawa University, 6-1-1 Tamagawa-gakuen, Machida, Tokyo 194-8610, Japan.
Acta Histochem Cytochem. 2008 Aug 28;41(4):83-8. doi: 10.1267/ahc.08004.
Functional maturation of the small intestine occurs during the weaning period in rats. It is known that this development is facilitated by glucocorticoid. However, the effect of glucocorticoid on morphological development of small intestine has yet to be clarified. The present study evaluated the morphological development and cell proliferation of the small intestine in adrenalectomized (ADX) rat pups. To further understand the mechanism of glucocorticoid effects on intestinal development, we examined the localization of the glucocorticoid receptor in the small intestine. Microscopic analysis showed that growth of villi and crypts is age-dependent, and is significantly attenuated in ADX rats compared with sham-operated rats. BrdU-positive cells, i.e. proliferating cells, were primarily observed in crypt compartments and rapidly increased in number during the early weaning period. The increase in BrdU-positive cells could be attenuated by adrenalectomy. The morphological development of small intestine may be associated with increased proliferation of epithelial cells. On the other hand, glucocorticoid receptors were found in epithelial cells of the mid- and lower villi and not in crypts where BrdU-positive cells were localized. These results indicate that the growth of small intestine is attenuated by adrenalectomy, and that glucocorticoid indirectly acts on proliferation of epithelial cells during the weaning period.
大鼠小肠的功能成熟发生在断奶期。已知糖皮质激素可促进这一发育过程。然而，糖皮质激素对小肠形态发育的影响尚未阐明。本研究评估了肾上腺切除（ADX）大鼠幼崽小肠的形态发育和细胞增殖情况。为了进一步了解糖皮质激素对肠道发育的作用机制，我们检测了糖皮质激素受体在小肠中的定位。显微镜分析表明，绒毛和隐窝的生长具有年龄依赖性，与假手术大鼠相比，ADX大鼠的绒毛和隐窝生长明显减弱。BrdU阳性细胞，即增殖细胞，主要出现在隐窝区，在断奶初期数量迅速增加。肾上腺切除术可减弱BrdU阳性细胞数量的增加。小肠的形态发育可能与上皮细胞增殖增加有关。另一方面，在绒毛中下段的上皮细胞中发现了糖皮质激素受体，而在BrdU阳性细胞所在的隐窝中未发现。这些结果表明，肾上腺切除术会减弱小肠的生长，且糖皮质激素在断奶期间接作用于上皮细胞的增殖。
