Laboratory for Infectious Diseases, Tokai University School of Medicine, Isehara 259-1193, Japan.
Appl Environ Microbiol. 2011 Oct;77(19):6964-71. doi: 10.1128/AEM.05230-11. Epub 2011 Jul 29.
It is known that the stomach is colonized by indigenous lactobacilli in mice. The aim of this study was to examine the role of such lactobacilli in the development of the stomach. For a DNA microarray analysis, germ-free BALB/c mice were orally inoculated with 10(9) CFU lactobacilli, and their stomachs were excised after 10 days to extract RNA. As a result, lactobacillus-associated gnotobiotic mice showed dramatically decreased expression of the gastrin gene in comparison to germ-free mice. The mean of the log(2) fold change in the gastrin gene was -4.3. Immunohistochemistry also demonstrated the number of gastrin-positive (gastrin(+)) cells to be significantly lower in the lactobacillus-associated gnotobiotic mice than in the germ-free mice. However, there was no significant difference in the number of somatostatin(+) cells in these groups of mice. Consequently, gastric acid secretion also decreased in the mice colonized by lactobacilli. In addition, an increase in the expression of the genes related to muscle system development, such as nebulin and troponin genes, was observed in lactobacillus-associated mice. Moreover, infection of germ-free mice with Helicobacter pylori also showed the down- and upregulation of gastrin and muscle genes, respectively, in the stomach. These results thus suggested that indigenous lactobacilli in the stomach significantly affect the regulation of gastrin-mediated gastric acid secretion without affecting somatostatin secretion in mice, while H. pylori also exerts such an effect on the stomach.
已知，胃内天然定植有本土乳杆菌。本研究旨在探究这些乳杆菌在胃发育过程中的作用。为进行 DNA 微阵列分析，将无菌 BALB/c 小鼠经口接种 10(9) CFU 乳杆菌，10 天后切取胃提取 RNA。结果显示，与无菌组相比，乳杆菌定植的无菌小鼠胃泌素基因的表达显著下调。胃泌素基因的 log(2) fold change 的平均值为-4.3。免疫组化也表明，乳杆菌定植的无菌小鼠胃泌素阳性（gastrin(+)）细胞数量明显少于无菌组。然而，这些组间的生长抑素（somatostatin(+)）细胞数量无显著差异。因此，乳杆菌定植的小鼠胃酸分泌也减少。此外，还观察到与肌肉系统发育相关的基因，如nebulin 和 troponin 基因的表达增加。此外，无菌小鼠感染幽门螺杆菌后，胃泌素和肌肉基因也分别表现出下调和上调。这些结果表明，胃内的本土乳杆菌显著影响胃泌素介导的胃酸分泌调节，而不影响生长抑素的分泌，而幽门螺杆菌也对胃产生这种影响。
