Lactobacillus plantarum B7 inhibits Helicobacter pylori growth and attenuates gastric inflammation.

Aim: To determine the anti-Helicobacter property of Lactobacillus plantarum B7 (L. plantarum) B7 supernatants in vitro and the protective effects of L. plantarum B7 on serum tumor necrosis factor-alpha (TNF-α), gastric malondialdehyde (MDA) level, apoptosis, and histopathology in Helicobacter pylori (H. pylori)-induced gastric inflammation in rats.

Methods: In vitro, the inhibition of H. pylori growth was examined using L. plantarum B7 supernatants at pH 4 and pH 7 and at the concentration of 1×, 5× and 10× on plates inoculated with H. pylori. The inhibitory effect of H. pylori was interpreted by the size of the inhibition zone. In vitro, male Sprague-Dawley rats were randomly divided into four groups including group 1 (control group), group 2 (H. pylori infected group), group 3 (H. pylori infected with L. plantarum B7 10(6) CFUs/mL treated group) and group 4 (H. pylori infected with L. plantarum B7 10(10) CFUs/mL treated group). One week after H. pylori inoculation, L. plantarum B7 10(6) CFUs/mL or 10(10) CFUs/mL were fed once daily to group 3 and group 4, respectively, for one week. Blood and gastric samples were collected at the end of the study.

Results: In vitro, at intact pH 4, mean inhibitory zone diameters of 8.5 mm and 13 mm were noted at concentrations of 5× and 10× of L. plantarum B7 supernatant disks, respectively. At adjusted pH 7, L. plantarum B7 supernatants at concentrations of 5× and 10× yielded mean inhibitory zone diameters of 6.5 mm and 11 mm, respectively. In the in vitro study, in group 2, stomach histopathology revealed mild to moderate H. pylori colonization and inflammation. The level of gastric MDA and epithelial cell apoptosis were significantly increased compared with group 1. The serum TNF-α level was significant decreased in group 3 compared with group 2 (P < 0.05). In addition, L. plantarum B7 treatments resulted in a significant improvement in stomach pathology, and decreased gastric MDA level and apoptotic epithelial cells.

Conclusion: L. plantarum B7 supernatant inhibits H. pylori growth. This inhibition was dose-dependent and greater at pH 4. Moreover, L. plantarum B7 attenuated H. pylori-induced gastric inflammation.