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至关重要， 预防多种胃肠道病变;然而这些机制 并不完全清楚。 我们的目的是确定参与的机制， 维持正常和旁路空肠的粘膜功能， 冬眠和活跃的13线地松鼠。 地松鼠不会 在冬眠期间进食或饮水，但运输功能出现 一直保存到春天发芽 这不同于 非冬眠哺乳动物肠道的营养物质转移， 通过禁食或肠道旁路手术，这会导致显著的 减少粘膜质量和吸收能力。 冬眠的松鼠 有完整肠道的冬眠动物， 手术，冬季活跃，喂养肠道正常的地松鼠， 冬季活跃，绕过松鼠将被用来测试假设， 在冬眠中的旁路肠被防止萎缩性变化 发生在非冬眠动物身上 小肠运输功能将 通过测量葡萄糖和钠的跨上皮通量来评估， 空肠段设置在改良的Ussing型腔室中， 以同时记录组织的电特性。 的 葡萄糖穿过刷状缘膜的单向流入将是 测量以确定葡萄糖载体位点的数量或 葡萄糖对其载体亲和力是适应性的原因 交通功能的变化。 每个细胞中的吸收细胞的质量 通过测量湿重和干重来估计实验组， 蛋白质和DNA含量的粘膜收获从邻近的节段， 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身上收集的， 分析肽和其他可能参与的信使 维持肠道结构和功能。 这些研究 预期将增进对有助于适应气候变化的机制的了解， 在冬眠期间维持肠道功能。

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.