Gama P, Alvares E P
Department of Histology and Embryology, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil.
J Nutr. 2000 Oct;130(10):2594-8. doi: 10.1093/jn/130.10.2564.
Food deprivation stimulates cell proliferation in the gastric epithelium of suckling, but not weanling rats. This study was designed to investigate the role of diet on proliferation in developing animals, using early weaning and prolonged nursing models. Rat pups were subjected to these dietary conditions at d 15 and were killed 3 or 7 d afterwards. One day before killing, half of pups were deprived of food. Body weights were recorded. After mitosis blockade, the histologic sections of the stomach were used for the evaluation of cell proliferation and methapasic cell distribution along the gland, and for the measurement of mucosa thickness. Body weight was impaired at 18 d by early weaning and at 22 d by prolonged nursing. Food restriction promoted a 10-15% weight loss regardless of dietary conditions. At 18 d, food deprivation inhibited cell division (P: < 0.01) and reduced the thickness of the mucosa (P: < 0.05) in rats that were weaned early. At 22 d, only the thickness of the mucosa was different between the groups that were subjected to early weaning and prolonged nursing (P: < 0.05), regardless of feeding state. The frequency of dividing cells along the gland was affected by early weaning in 18- and 22-d-old rats. These results suggest the following: 1) food deprivation effects are dependent on dietary condition at 18 d because different proliferative responses were achieved after early weaning and prolonged nursing; 2) the lack of changes after dietary manipulation in 22-d-old rats indicates a nonresponsive period during postnatal development. We conclude that milk is a modulatory factor for cell proliferation in the gastric mucosa of rats.
食物剥夺会刺激乳鼠而非断奶幼鼠胃上皮细胞的增殖。本研究旨在利用早期断奶和延长哺乳模型，探讨饮食对发育中动物细胞增殖的作用。在第15天将幼鼠置于这些饮食条件下，并在3天或7天后处死。处死前一天，将一半幼鼠禁食。记录体重。在有丝分裂阻断后，胃组织切片用于评估细胞增殖和沿腺体的中期细胞分布，以及测量黏膜厚度。早期断奶会导致18日龄时体重受损，延长哺乳则会导致22日龄时体重受损。无论饮食条件如何，食物限制都会使体重减轻10 - 15%。在18日龄时，食物剥夺抑制了早期断奶大鼠的细胞分裂（P < 0.01）并降低了黏膜厚度（P < 0.05）。在22日龄时，无论喂养状态如何，早期断奶组和延长哺乳组之间仅黏膜厚度存在差异（P < 0.05）。在18日龄和22日龄大鼠中，沿腺体的分裂细胞频率受早期断奶影响。这些结果表明：1）18日龄时食物剥夺的影响取决于饮食条件，因为早期断奶和延长哺乳后出现了不同的增殖反应；2）22日龄大鼠饮食操作后无变化表明出生后发育存在一个无反应期。我们得出结论，乳汁是大鼠胃黏膜细胞增殖的调节因子。
