INTESTINAL PROTEIN METABOLISM IN SEPSIS

脓毒症中的肠道蛋白质代谢

基本信息

批准号：
2143612
负责人：
PER-OLOF J HASSELGREN
金额：
$ 9.31万
依托单位：
UNIVERSITY OF CINCINNATI
依托单位国家：
美国
项目类别：
财政年份：
1992
资助国家：
美国
起止时间：
1992-04-01 至 1995-03-31
项目状态：
已结题

项目摘要

Protein synthesis is an important function of the intestine, both from a quantitative and qualitative standpoint. The aim of this project is to determine the effect of sepsis on intestinal protein metabolism, synthesis and release of gut peptides, and enterocyte proliferation and migration rates. We will also test the hypothesis that TNF, IL-1 and IL-6 regulate intestinal protein metabolism during sepsis. Finally, we will study the effect of glutamine on protein synthesis in isolated enterocytes from control and septic rats. Sepsis is induced in rats by cecal ligation and puncture (CLP); controls are sham-operated. Protein synthesis rate is measured in vivo in jejunal and ileal mucosa and serosa using a flooding dose of 14C-leucine. In other experiments, protein turnover rates are determined in isolated enterocytes from control and septic rats. Because changes in intestinal protein turnover may reflect altered cellular protein metabolism and or altered cell proliferation rates, cell proliferation is studied by determining incorporation of radioactivity into DNA and by performing autoradiographic studies following the administration of 3H- thymidine (1 mu-Ci/g b.w.). The effect of sepsis on gut hormone synthesis and release is determined by measuring plasma levels of vasoactive intestinal peptide (VIP), peptide YY (PYY), secretion and gastrin in control and septic rats, synthesis of VIP and PYY by isolated enterocytes, and mRNA levels for VIP and PYY in intestinal wall. The role of TNF, IL-1 and IL-6 is elucidated by plasma and tissue (intestinal wall) levels of the cytokines in the septic model and by administering the cytokines (100 mu- g/kg bw i.p. in three repeated does over 16 h) to normal rats followed by measurement of intestinal protein turnover rates. The effect of cytokine antisera administered 2 h before induction of sepsis on intestinal protein synthesis rate will also be tested. Finally, the effect of glutamine on protein synthesis is tested by incubating isolated enterocytes with different concentrations (up to 3.4 micro M) of the amino acid. The effect of glutamine is compared to that of acetoacetate and 3-hydroxybutyrate to test the hypothesis that any effect of glutamine on enterocyte protein synthesis is caused by energy provision. The proposed studies are important because changes in intestinal protein metabolism during sepsis may greatly influence total body protein economy and may also be related to changes in other intestinal functions during sepsis and critical illness.

蛋白质合成是肠的重要功能，均来自A 定量和定性的角度。这个项目的目的是确定败血症对肠道蛋白质代谢的影响，合成并释放肠道肽，肠肠细胞增殖和迁移费率。我们还将测试TNF，IL-1和IL-6调节的假设败血症期间的肠道蛋白质代谢。最后，我们将研究谷氨酰胺对分离的肠细胞中蛋白质合成的影响控制和化粪池大鼠。败血症是通过盲肠连接在大鼠中诱导的穿刺（CLP）;对照是假操作的。蛋白质合成率为使用洪水在空肠和卵形粘膜和浆膜中进行体内测量剂量为14c-达氨酸。在其他实验中，蛋白质更新率为在对照和化粪池大鼠的分离肠上皮细胞中确定。因为肠蛋白周转率的变化可能反映了细胞蛋白的改变代谢和 /或 /或 /或 /或改变细胞增殖率，细胞增殖为通过确定放射性纳入DNA和执行3H-之后，进行放射自显影研究胸苷（1 Mu-CI/G B.W.）。败血症对肠激素合成的影响并通过测量血管活性的血浆水平来确定释放肠肽（VIP），肽YY（PYY），分泌和胃蛋白对照和化粪池大鼠，由孤立的肠上皮细胞合成VIP和PYY，和在肠壁中进行VIP和PYY的mRNA水平。 TNF，IL-1的作用 IL-6通过血浆和组织（肠壁）水平阐明化粪池模型中的细胞因子并通过施用细胞因子（100 mu-- g/kg bw i.p.在三个重复中确实超过16 h）到正常大鼠，然后肠蛋白周转率的测量。细胞因子的作用抗脓毒症在肠蛋白上诱导之前2小时给药合成率也将进行测试。最后，谷氨酰胺对通过将分离的肠上皮细胞与氨基酸的不同浓度（高达3.4微米）。效果将谷氨酰胺与乙酸乙酸盐和3-羟基丁酸的谷氨酸进行比较。检验谷氨酰胺对肠上皮蛋白的任何作用的假设合成是由能源提供引起的。拟议的研究是重要，因为脓毒症期间肠道蛋白质代谢的变化可能会极大地影响总体蛋白质经济，也可能与败血症和危重疾病期间其他肠功能的变化。