Holt P R, Tierney A R, Kotler D P
Gastroenterology. 1985 Nov;89(5):1026-34. doi: 10.1016/0016-5085(85)90204-5.
To evaluate the effect of aging upon the small intestine, the distribution, content, and concentration of epithelial cell enzymes at different levels along the crypt-villus column were measured in aging and young adult, male, Fisher 344 rats. Specific activities of sucrase, maltase, lactase, and adenosine deaminase in mucosal homogenates were lower in the upper intestines of aging than in young animals, whereas the specific activity and content of thymidine kinase was higher. Enzyme activities were measured in cells obtained by cryostat sectioning from villus tip to crypt base. Sucrase and maltase activities were fully expressed nearest the crypt, alkaline phosphatase in cells higher on the villus, and adenosine deaminase higher still, whereas thymidine kinase activity was limited to the crypts. The ordered pattern of enzyme expression was maintained in aging rats but the initiation and duration were delayed. Because peak specific enzyme activities were similar in young and aging animals, the reduced specific activities in mucosal homogenates from aging animals were due to an increase in the proportion of relatively undifferentiated villus epithelial cells. These findings are of importance in explaining altered intestinal function during aging without a concomitant change in intestinal structure.
为评估衰老对小肠的影响，在衰老和年轻成年雄性费希尔344大鼠中，对沿隐窝-绒毛柱不同水平的上皮细胞酶的分布、含量和浓度进行了测量。衰老大鼠上肠黏膜匀浆中蔗糖酶、麦芽糖酶、乳糖酶和腺苷脱氨酶的比活性低于年轻动物，而胸苷激酶的比活性和含量则较高。通过低温切片从绒毛顶端到隐窝底部获取细胞并测量酶活性。蔗糖酶和麦芽糖酶活性在最靠近隐窝处充分表达，碱性磷酸酶在绒毛较高位置的细胞中表达，腺苷脱氨酶表达更高，而胸苷激酶活性仅限于隐窝。衰老大鼠中酶表达的有序模式得以维持，但起始和持续时间延迟。由于年轻和衰老动物的峰值比酶活性相似，衰老动物黏膜匀浆中比活性降低是由于相对未分化的绒毛上皮细胞比例增加。这些发现对于解释衰老过程中肠道功能改变而肠道结构无相应变化具有重要意义。
