Mitani-Ehara S
Third Department of Internal Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
Hokkaido Igaku Zasshi. 1994 Jul;69(4):836-46.
The cause of gastric mucosal cell injury induced by Helicobacter pylori (H. pylori) was investigated in vitro using gastric mucosal cells derived from the stomach of male Japanese white rabbits. In order to evaluate the contribution of potent urease activity of H. pylori to gastric mucosal cell injury, supernatant of H. pylori bacterial pellet solubilized in a 1.0% solution of n-octyl-glucoside, the H. pylori extracts, was added to the rabbit gastric mucosal cell suspension. Cell injury was expressed by LDH release into the extracellular fluid of gastric mucosal cell suspension after 30 minutes incubation at 37 degrees C. Treatment of cells by H. pylori extracts (final concentration of 0.54 mg/ml) together with urea (final concentration at 50 mM) showed a high LDH release into the extracellular fluid suggesting definite gastric mucosal cell injury. Elevation of ammonia concentration and that of extracellular fluid pH were also observed by the treatment, whereas H. pylori extracts alone and urea solution alone did not. The ammonia concentration of extracellular fluid and LDH release were distinctly elevated in accord with increasing amount of H. pylori extracts under the existence of 50 mM urea. The degree of LDH release from gastric mucosal cell by H. pylori extracts under the existence of urea was similar to that induced by the administration of the same amount of exogenous ammonia. The addition of acetohydroxamic acid (AHA), a potent specific urease inhibitor, remarkably inhibited dose dependently the ammonia production, the elevation of pH of extracellular fluid and LDH release induced by H. pylori extracts under the presence of urea. These results suggest that the ammonia produced by potent urease activity of H. pylori under the presence of urea played an important role in the pathogenesis of gastric mucosal cell injury.
利用雄性日本白兔胃黏膜细胞在体外研究幽门螺杆菌（H. pylori）诱导胃黏膜细胞损伤的原因。为了评估幽门螺杆菌强大的脲酶活性对胃黏膜细胞损伤的作用，将溶解于1.0%正辛基 - 葡萄糖苷溶液中的幽门螺杆菌菌体重悬液上清液（幽门螺杆菌提取物）添加到兔胃黏膜细胞悬液中。在37℃孵育30分钟后，通过胃黏膜细胞悬液细胞外液中乳酸脱氢酶（LDH）的释放来表示细胞损伤。用幽门螺杆菌提取物（终浓度0.54 mg/ml）联合尿素（终浓度50 mM）处理细胞，结果显示细胞外液中有大量LDH释放，提示胃黏膜细胞受到明确损伤。处理后还观察到氨浓度和细胞外液pH值升高，而单独使用幽门螺杆菌提取物和单独使用尿素溶液时则未出现这种情况。在50 mM尿素存在的情况下，随着幽门螺杆菌提取物用量增加，细胞外液氨浓度和LDH释放明显升高。在尿素存在时，幽门螺杆菌提取物引起的胃黏膜细胞LDH释放程度与等量外源性氨诱导的相似。添加乙酰氧肟酸（AHA），一种有效的特异性脲酶抑制剂，在尿素存在时能显著剂量依赖性地抑制幽门螺杆菌提取物诱导的氨生成、细胞外液pH值升高和LDH释放。这些结果表明，在尿素存在时，幽门螺杆菌强大的脲酶活性产生的氨在胃黏膜细胞损伤的发病机制中起重要作用。
