Tomikawa M, Akiba Y, Kaunitz J D, Kawanaka H, Sugimachi K, Sarfeh I J, Tarnawski A S
Departments of Medicine and Surgery, Veterans Affairs Medical Center, Long Beach, CA 90822, USA.
J Gastrointest Surg. 2000 Sep-Oct;4(5):458-63. doi: 10.1016/s1091-255x(00)80086-4.
Portal hypertension (PHT) increases susceptibility of the gastric mucosa to injury. The aim of this study was to investigate whether PHT affects rat gastric mucosal defense mechanisms in vivo at the pre-epithelial, epithelial, and/or post-epithelial levels. PHT was produced in rats by staged portal vein ligation and sham-operated (SO) rats served as controls. The gastric mucosa was exposed, chambered, and continuously superfused with buffers under in vivo microscopy. We measured gastric mucosal gel layer thickness, surface epithelial cell intracellular pH (pHi), mucosal blood flow, and mucosal/serosal oxygenation. In PHT rats, gastric mucosal gel layer thickness was significantly reduced (88 +/- 16 microm in PHT rats vs. 135 +/- 25 microm in SO rats; P <0.0001), and the surface epithelial cell pHi was significantly decreased (6.80 +/- 0.11 in PHT rats vs. 7.09 +/- 0.21 in SO rats; P <0.01). Although total gastric mucosal blood flow was significantly increased in PHT rats by 72% (P <0.05), the oxygenation of the gastric mucosal surface was decreased by 42% (P <0.05) compared with SO rats. PHT impairs pre-epithelial (mucosal gel layer thickness), epithelial (pHi), and post-epithelial (maldistribution of blood flow) components of the gastric mucosal barrier. These findings can explain the increased susceptibility of portal hypertensive gastric mucosa to injury.
门静脉高压症（PHT）会增加胃黏膜对损伤的易感性。本研究的目的是调查PHT是否会在体内上皮前、上皮和/或上皮后水平影响大鼠胃黏膜防御机制。通过分期门静脉结扎在大鼠中制造PHT，假手术（SO）大鼠作为对照。在体内显微镜下暴露胃黏膜，进行分隔，并持续用缓冲液灌注。我们测量了胃黏膜凝胶层厚度、表面上皮细胞细胞内pH值（pHi）、黏膜血流量和黏膜/浆膜氧合情况。在PHT大鼠中，胃黏膜凝胶层厚度显著降低（PHT大鼠为88±16微米，SO大鼠为135±25微米；P<0.0001），表面上皮细胞pHi显著降低（PHT大鼠为6.80±0.11，SO大鼠为7.09±0.21；P<0.01）。尽管PHT大鼠的胃黏膜总血流量显著增加了72%（P<0.05），但与SO大鼠相比，胃黏膜表面的氧合降低了42%（P<0.05）。PHT损害了胃黏膜屏障的上皮前（黏膜凝胶层厚度）、上皮（pHi）和上皮后（血流分布不均）成分。这些发现可以解释门静脉高压性胃黏膜对损伤的易感性增加。
