INTESTINAL BYPASS SURGERY IN HIBERNATION

了解哺乳动物肠道适应性的机制 调节其结构和功能对治疗和 预防多种胃肠道疾病；然而这些机制 目前还不完全清楚。我们的目标是确定参与 正常和旁路空肠粘膜功能的维持 冬眠和活跃的13行地松鼠。地松鼠不会 在冬眠期间吃或喝，但运输功能出现 保存下来，直到春天出现。与此形成对比的是 从非冬眠的哺乳动物肠道中转移营养物质 通过禁食或肠道搭桥手术，这会导致显著的 减少粘膜质量和吸收能力。冬眠松鼠 肠道完好的冬眠者，接受肠道搭桥的冬眠者 外科手术，冬季活动，喂养具有正常肠道和 冬季活动的绕过的松鼠将被用来检验这一假设 冬眠者绕过的肠子可防止萎缩性改变 发生在非冬眠者身上。将发挥小肠转运功能 通过测量葡萄糖和钠在血管内皮细胞中的跨上皮通量来评估 空肠段设置在改进的Ussing类型的腔室中，配备 以同时记录组织的电特性。这个 葡萄糖通过刷子边缘膜的单向流入将是 测量以确定葡萄糖携带部位的数量是否发生变化或 葡萄糖对其载体的亲和力负责适应 运输功能的变化。每个细胞中吸收细胞的质量 试验组将通过测量湿重和干重来评估， 邻近节段粘膜的蛋白质和DNA含量 用于生理学实验。血液和组织样本将 从运输实验中使用的松鼠中收集，供以后使用 分析可能涉及到的多肽和其他信使 维持肠道结构和功能。这些研究是 期望加强对有助于适应的机制的理解 冬眠期间肠道功能的维持。

Knowledge of the mechanisms by which the mammalian intestine adaptively regulates its structure and function is essential to the treatment and prevention of numerous gastrointestinal pathologies; yet these mechanisms are not entirely clear. Our aim is to identify mechanisms involved in the maintenance of mucosal function of normal and bypassed jejunum in hibernating and active 13-lined ground squirrels. Ground squirrels do not eat or drink during the hibernation period, yet transport function appears to be preserved until emergence in the spring. This is in contrast to diversion of nutrients from the non-hibernating mammalian intestine, either by fasting or intestinal bypass surgery, which results in significant reductions in mucosal mass and absorptive capacity. Hibernating squirrels with intact intestines, hibernators that have undergone intestinal bypass surgery, winter-active, fed ground squirrels with normal intestines and winter active, bypassed squirrels will be used to test the hypothesis that bypassed intestine in the hibernator is prevented from the atrophic changes that occur in non-hibernators. Small intestinal transport function will be assessed by measuring transepithelial fluxes of glucose and sodium in jejunal segments set up in modified Ussing-type chambers that are equipped to simultaneously record electrical properties of the tissue. The unidirectional influx of glucose across the brush border membrane will be measured to determine if changes in the number of glucose carrier sites or the affinity of glucose for its carrier are responsible for adaptive changes in transport function. The mass of absorptive cells in each experimental group will be estimated by measuring the wet and dry weights, protein and DNA content of mucosa harvested from segments adjacent to those used in the physiological experiments. Blood and tissue samples will be collected from squirrels used in the transport experiments for later analysis of peptides and other messengers that might be involved in the maintenance of intestinal structure and function. These studies are expected to enhance understanding of mechanisms that contribute to adaptive maintenance of intestinal function during hibernation.