Effects of Lacticaseibacillus paracasei HP7 Against Helicobacter pylori-Induced Gastric Mucosal Inflammation and Mucosal Protection.

Helicobacter pylori (H. pylori) is a major pathogen that colonizes the human gastric surface and induces chronic inflammation and mucosal damage, leading to various gastric diseases. This study examined the gastroprotective effects of Lacticaseibacillus paracasei HP7 in an H. pylori-infected animal model. Male C57BL/6 mice were divided into four groups: normal control, H. pylori-infected control (HP), H. pylori-infected group treated with live L. paracasei HP7 for 4 weeks (L-HP7), and H. pylori-infected group treated with heat-killed L. paracasei HP7 for 4 weeks (HK-HP7). The results showed that serum histamine and gastrin levels, as well as gastric mucosal inflammatory cytokine mRNA levels, including interleukin (IL)-1β, IL-6, IL-8, IL-18, interferon gamma, and tumor necrosis factor alpha, were significantly reduced in both the L-HP7 and HK-HP7 groups. Histopathological scoring of hematoxylin & eosin-stained gastric mucosal tissues also showed significant improvements in both groups. Serum anti-H. pylori immunoglobulin G (IgG) and CCK2R mRNA levels decreased in the L-HP7 group, whereas MUC1 mRNA levels increased. Collectively, these findings indicate that L. paracasei HP7, in both live and heat-killed forms, protects gastric surface epithelial and mucosal cells and alleviates inflammatory status by reducing the expression of pro-inflammatory cytokines. L. paracasei HP7 may serve as a promising adjunct to antibiotics in the management of H. pylori-associated diseases.