Effects of <i>Lacticaseibacillus paracasei</i> HP7 Against <i>Helicobacter pylori</i> -Induced Gastric Mucosal Inflammation and Mucosal Protection

<i>Helicobacter pylori</i> (<i>H. pylori</i>) 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 <i>Lacticaseibacillus paracasei</i> HP7 in an <i>H. pylori</i>-infected animal model. Male C57BL/6 mice were divided into four groups: normal control, <i>H. pylori</i>-infected control (HP), <i>H. pylori</i>-infected group treated with live <i>L. paracasei</i> HP7 for 4 weeks (L-HP7), and <i>H. pylori</i>-infected group treated with heat-killed <i>L. paracasei</i> 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-<i>H. pylori</i> immunoglobulin G (IgG) and CCK2R mRNA levels decreased in the L-HP7 group, whereas MUC1 mRNA levels increased. Collectively, these findings indicate that <i>L. paracasei</i> 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. <i>L. paracasei</i> HP7 may serve as a promising adjunct to antibiotics in the management of <i>H. pylori</i>-associated diseases.