The Role of the Gut in the Surgical Stress

我们做了以下两项关于肠道在手术应激中的作用的研究。为了比较术后肠内和肠外营养对蛋白质动力学、肠道完整性和免疫以及激素环境的影响，8只胃切除大鼠接受了3或7天的肠内（IG组）或肠外营养（IV组）。与POD 3相比，IG组的整体蛋白质分解在POD 7时显著降低，而IV组无变化。术后腓肠肌、腹直肌分段合成率IG组较高。IG组术后小肠蛋白质合成较IV组活跃。术后第3天，IG组结肠IgA阳性细胞和胸腺髓质淋巴细胞数量均高于IV组。结论：1.肠道在手术应激中起重要作用，肠内营养较肠外营养能更好地改善蛋白质代谢和全身免疫功能.第二项研究探讨了IL-1和TNF对长期插管清醒犬的血流动力学参数和器官间底物通量的影响。犬静脉内接受5 mcg/kg. h的人重组IL-1或TNF，持续2小时。IL-1和TNF均增强肝脏对丙氨酸的摄取、乳酸的摄取和葡萄糖的输出。IL-1产生高动力状态，增加内脏血流量，并增强肠道对谷氨酰胺的摄取。相反，TNF既不产生高动力状态，也不改变肠道对氨基酸的处理。我们得出结论，IL-1和TNF发挥不同的影响，全身和内脏血流动力学的改变，和氨基酸通量通过肠道和肝脏。

We did the following two studies about the role of the gut in surgical stress.1. To compare the effects of postoperative enteral and parenteral nutrition on protein dynamics, gut integrity and immunity, and hormonal environment, eight gastrectomized rats underwent either entral (IG group) or parenteral nutrition (IV group) for 3 or 7 days. Whole body protein breakdown of the IG group significantly decreased at POD 7 compared to that at POD 3, while no change in the IV group. The postoperative fractional synthesis rate of gastrocnemius muscle and rectus abdominis muscle were higher in the IG group. than those in the IV group Postoperative protein synthesis in the small intestine was more active in the IG group than in the IV group. Both colonic lgA-containing cells and lymphocytles of thymus medulla in the IG group outnumbered those in the IV group at POD 3. We conclude that the gut plays an important role in the surgical stress and enteral nutrition may improve protein metabolism and systemic immunity better than parenteral nutrition.2. The second study examines the effects of IL-1 and TNF on hemodynamic parameters and inter-organ fluxes of substrates in chronically catheterized awake dogs. The dogs received 5mcg/kg.hour of either human recombinant IL-1 or TNF intravenously for two hours. Both IL-1 and TNF enhanced the uptake of alanine, uptake of lactate and output of glucose by the liver. IL-1 produced hyperdynamic state, increased splanchnic blood flow and enhanced glutamine uptake by the gut. On the contrary, TNF produced neither hyperdynamic state nor alter the gut handling of amino acids. We conclude IL-1 and TNF exert distinct different effects as to the alterations of systemic and splanchnic hemodynamics, and amino acids fluxes across the gut and liver.