ESOPHAGEAL CYTOPROTECTION--AGENTS AND MECHANISMS

食管细胞保护——代理和机制

• 批准号: 3234326
• 负责人: Roy Charles Orlando
• 金额: $ 23.53万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-08-01 至 1994-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3234326
• 关键词: acidity /alkalinity; acids; antibody formation; cellular pathology; chromium; cryoprotective agents; cytology; cytolysis; diffusion; disease /disorder proneness /risk; divalent cations; divalent metal; esophagus; gastrointestinal absorption /transport; gastrointestinal epithelium; gel electrophoresis; histochemistry /cytochemistry; hydrogen transport; immunofluorescence technique; laboratory rabbit; molybdenum; nonelectrolyte transport; nuclear magnetic resonance spectroscopy; radiotracer; reflux esophagitis; secretion; selenium; sucrose; sulfates; tungsten

The overall goals of this proposal are: a) to gain insight into the pathogenesis of reflux esophagitis and b) to establish alternative means (other than by acid inhibition) for its prevention and treatment. The specific aims can be divided into 3 parts. The first part explores a novel mechanism for acid clearance by mammalian esophagus - that of esophageal bicarbonate (HCO3) secretion. Initially described in possums, the present studies will determine by ph-stat and ph-probe techniques whether he in vivo human esophagus, in health and reflux disease, secretes HCO3 and, if so, its capacity for acid clearance. The mechanisms of esophageal HCO3 secretion will also e explored using Ussing-chambered opossum mucosa and ph-stat technique. The second part tests the following hypothesis: luminal acid damages esophagus because H+ diffuse through the paracellular pathway then gain entry to the cell across the basolateral membrane on proteins normally used for regulation of intracellular pH (pHi). The hypothesis is tested by performing detailed studies of junctional morphology using electron microscopy with tracers, light microscopy with histochemical staining, and freeze fracture techniques and by studies of pHi regulatory processes in healthy and acid-exposed isolated cells (flourescent dye, BCECF, technique) and intact epithelium distribution of the weak acid, DMO, and 31P-NMR spectroscopy). The third part is to determine: a) the site and mechanisms of action of 3 groups of agents that protect the rabbit esophagus against acid damage without inhibiting acid secretion cytoprotection), and b) the capacity of these agents to prevent in experimental animals acid damage to gastric or duodenal epithelium and in humans acid damage to esophageal epithelium. Identification of mechanism/site of action will be carried out by the binding of radiolabelled CP agents to tissue. Tissues are then studied by utoradiography and SDS polyacrylamide gel electrophoresis, the latter to isolate proteins for production of antibodies for flourescein labelling. For studies of protection by CP agents, the change in resistance (and morphology) of acid-exposed Ussing-chambered epithelia from rabbit esophagus or duodenum will be assessed while protection of rat stomach against acid damage is assessed morphologically after in vivo gavage. Protection by Na 2SO4 is tested in the acid-perfused human esophagus in vivo by simultaneous measurements of esophageal potential difference.

该提案的总体目标是：a）了解 反流食管炎和b）建立替代手段的发病机理 （除了通过酸抑制）预防和治疗。这 具体目标可以分为3个部分。第一部分探索了 哺乳动物食管酸清除的新机制 - 食管碳酸氢盐（HCO3）分泌。最初在负鼠中描述 本研究将通过pH-Stat和pH探针技术确定 无论他体内人类食管，健康和反流疾病， 分泌HCO3，如果是这样，则其酸清除能力。机制 食管HCO3分泌也将使用Ussing-Chambered探索 负鼠粘膜和pH-Stat技术。第二部分测试以下 假设：发光酸会损害食道，因为H+通过 细胞细胞途径然后进入基底外侧进入细胞 通常用于调节细胞内pH的蛋白质上的膜 （phi）。通过对 使用电子显微镜和示踪剂，光，光 带有组织化学染色的显微镜，并冻结断裂技术 通过研究健康和酸暴露的PHI调节过程 分离的细胞（粉料染料，BCECF，技术）和完整的上皮 弱酸，DMO和31P-NMR光谱的分布）。第三 部分是确定：a）3组的位点和作用机理 保护兔食管免受酸损伤的药物没有 抑制酸分泌的细胞保护），b）这些能力 防止实验动物酸损害胃或 十二指肠上皮和人类对食管上皮的损害。 机理/作用部位的识别将由 放射性标记的CP药物与组织的结合。然后通过 Utoradiography和SDS聚丙烯酰胺凝胶电泳，后者 分离蛋白用于生产用于粉状标记的抗体。 对于CP代理的保护研究，抗药性的变化（和 酸暴露于兔子的酸性上皮的形态） 在保护大鼠胃的同时，将评估食道或十二指肠 在体内饲养后，对酸损伤进行了形态学评估。 Na 2SO4的保护在酸化的人食管中测试 通过同时测量食道电位差异。