INTESTINAL PROTEIN METABOLISM IN SEPSIS

脓毒症中的肠道蛋白质代谢

• 批准号: 3245725
• 负责人: PER-OLOF J HASSELGREN
• 金额: $ 8.7万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 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
• 来源: https://reporter.nih.gov/project-details/3245725
• 关键词: aminoacid transport; autoradiography; cell cycle; cell migration; cytokine; cytokine receptors; deoxyglucose; gastrins; glucose transport; glutamine; interferons; interleukin 1; interleukin 6; intestinal mucosa; intestines; laboratory rat; neuropeptide Y; protein biosynthesis; protein metabolism; proteolysis; radiotracer; secretin; tumor necrosis factor alpha; vasoactive intestinal peptide

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.

蛋白质合成是肠道的重要功能， 定量和定性的观点。 该项目的目的是 确定脓毒症对肠道蛋白质代谢、合成的影响 肠肽的释放以及肠上皮细胞的增殖和迁移 费率。 我们还将检验 TNF、IL-1 和 IL-6 调节的假设 脓毒症期间肠道蛋白质代谢。 最后，我们将研究 谷氨酰胺对分离肠上皮细胞蛋白质合成的影响 对照和败血症大鼠。 通过盲肠结扎诱导大鼠败血症 穿刺（CLP）；控制是假操作的。 蛋白质合成率为 使用洪水在体内测量空肠和回肠粘膜和浆膜 14C-亮氨酸的剂量。 在其他实验中，蛋白质周转率是 在来自对照和脓毒症大鼠的分离的肠细胞中测定。 因为 肠道蛋白质周转的变化可能反映了细胞蛋白质的改变 代谢和/或改变细胞增殖率，细胞增殖是 通过确定放射性掺入 DNA 并通过 施用 3H- 后进行放射自显影研究 胸苷（1 mu-Ci/g b.w.）。 脓毒症对肠道激素合成的影响 并通过测量血管活性物质的血浆水平来确定释放 肠肽（VIP）、肽YY（PYY）、分泌物和胃泌素 对照和脓毒症大鼠，通过分离的肠上皮细胞合成 VIP 和 PYY， 肠壁中 VIP 和 PYY 的 mRNA 水平。 TNF、IL-1的作用 IL-6 通过血浆和组织（肠壁）水平来阐明 脓毒症模型中的细胞因子以及通过施用细胞因子（100μ- g/kg 体重 i.p.在 16 小时内对正常大鼠重复 3 次，然后 测量肠道蛋白质周转率。 细胞因子的作用 在诱导肠蛋白败血症前 2 小时给予抗血清 合成率也将被测试。 最后，谷氨酰胺的作用 通过将分离的肠上皮细胞与 不同浓度（高达 3.4 微 M）的氨基酸。 效果 谷氨酰胺与乙酰乙酸和 3-羟基丁酸的比较 检验以下假设：谷氨酰胺对肠上皮细胞蛋白有任何影响 合成是由能量供应引起的。 拟议的研究是 重要的是因为败血症期间肠道蛋白质代谢的变化 可能极大地影响全身蛋白质经济，也可能与 脓毒症和危重疾病期间其他肠道功能的变化。