Lin C H, Correia L, Tolia K, Gesell M S, Tolia V, Lee P C, Luk G D
Departments of Pediatrics, Wayne State University and Childrens Hospital of Michigan, Detroit, MI 48201, USA.
J Nutr. 1998 Oct;128(10):1636-42. doi: 10.1093/jn/128.10.1636.
Increased ornithine decarboxylase (ODC) activity is associated with rapid cell proliferation in many cell types. The cellular effects of early weaning on intestinal development are not well established. To investigate whether ODC is involved in intestinal growth after early weaning, we precociously weaned suckling rats on postnatal d 15 and followed through d 21 (6 d after early weaning). Age-matched suckling pups served as controls. Rat pups were killed 1, 2, 3 and 6 d after early weaning and jejunal mucosa was assayed for ODC and sucrase activities, and protein and DNA contents. Jejunal cell proliferation was monitored by bromodeoxyuridine immunohistochemistry. Elevated jejunal ODC activity 1 d after early weaning was the earliest cellular event that was detected in the current study. ODC activity peaked at d 3 (about 15-fold greater than age-matched unweaned suckling controls). Sucrase activity was elevated at d 2 after weaning and peaked at d 3 (about 10-fold greater than controls). Greater bromodeoxyuridine immunostaining in early weaned rats occurred on d 3. Protein and DNA contents were greater in jejunal mucosa of early weaned rats at d 6. Serum corticosterone levels were elevated on d 1 and d 2 after early weaning compared to controls. To explore whether the intake of nonpurified diet played a role, we also compared the induction of jejunal ODC activity in early weaned pups and pups that were food-deprived for 1 d. ODC activity was not greater in the food-deprived group compared to suckling controls while the early weaned group had 6-fold greater activity 1 d after early weaning. Early weaning stimulates jejunal cell proliferation and differentiation. The temporal sequence of increased ODC activity followed by increases in other growth variables suggests that the induction of ODC activity may act as an early marker of intestinal growth during early weaning.
鸟氨酸脱羧酶（ODC）活性增加与多种细胞类型的快速细胞增殖相关。早期断奶对肠道发育的细胞影响尚未完全明确。为了研究ODC是否参与早期断奶后的肠道生长，我们在出生后第15天对乳鼠进行过早断奶，并持续观察至第21天（早期断奶后6天）。年龄匹配的哺乳幼崽作为对照。在早期断奶后1、2、3和6天处死幼鼠，检测空肠黏膜的ODC和蔗糖酶活性、蛋白质和DNA含量。通过溴脱氧尿苷免疫组织化学监测空肠细胞增殖。早期断奶后1天空肠ODC活性升高是本研究中检测到的最早细胞事件。ODC活性在第3天达到峰值（比年龄匹配的未断奶哺乳对照高约15倍）。蔗糖酶活性在断奶后第2天升高，并在第3天达到峰值（比对照高约10倍）。早期断奶大鼠在第3天出现更强的溴脱氧尿苷免疫染色。早期断奶大鼠在第6天空肠黏膜中的蛋白质和DNA含量更高。与对照组相比，早期断奶后第1天和第2天血清皮质酮水平升高。为了探讨非纯化饮食的摄入是否起作用，我们还比较了早期断奶幼崽和禁食1天幼崽空肠ODC活性的诱导情况。与哺乳对照相比，禁食组的ODC活性没有更高，而早期断奶组在早期断奶后1天的活性高6倍。早期断奶刺激空肠细胞增殖和分化。ODC活性增加后其他生长变量随之增加的时间顺序表明，ODC活性的诱导可能作为早期断奶期间肠道生长的早期标志物。
