Establishment of BALB/c mice model infected with Helicobacter pylori

Astaxanthin Inhibits Helicobacter pylori-induced Inflammatory and Oncogenic Responses in Gastric Mucosal Tissues of Mice

Helicobacter pylori is recognized as a risk factor for gastric carcinogenesis. The chronic exposure of gastric epithelium to H. pylori induces a prolonged inflammatory state that may progress to gastric cancer. Astaxanthin, a pinkish antioxidant carotenoid, abundant in marine organisms, is known for its protective effect against inflammation and multiple types of cancer. The purpose of this study was to examine the effect of astaxanthin on H. pylori-induced oxidative injury, inflammation, and oncogene expression in gastric mucosal tissues of the infected mice. Mice were inoculated using oral gavage with H. pylori suspension (10⁸ colony forming unit of H. pylori/0.1 mL) for three days, after which they were fed astaxanthin-supplemented diet (5 mg/kg body weight/day for seven weeks). The effects of astaxanthin on H. pylori-induced increase in lipid peroxide (LPO) production, myeloperoxidase (MPO) activity, expression of the inflammatory cytokine IFN-_γ and oncogenes (c-myc and cyclin D1), and the accompanying histologic changes in gastric mucosal tissues were evaluated. H. pylori infection increased the level of LPO, MPO activity, and the expression of IFN-_γ, c-myc, and cyclin D1 in gastric mucosal tissues of mice. H. pylori infection induced neutrophil infiltration and hyperplasia of gastric mucosa. Astaxanthin supplementation attenuated these effects. In conclusion, consumption of astaxanthin-rich foods may prevent H. pylori-associated oxidative damage and inflammatory and oncogenic responses in gastric mucosal tissues.

RKIP and peroxiredoxin 2 expression predicts the proliferative potential of gastric cancer stem cells

Gastric cancer is associated with a high mortality rate, with the development of gastric cancer stem cells underlying this. Gastric cancer stem cells are responsible for tumor initiation, progression and recurrence. However, the link between gastric cancer and gastric cancer stem cells remains to be fully understood. Murine models mimic a human microenvironment more accurately than in vitro studies and are useful models for understanding the behavior of different markers. The present study compared the expression of cluster of differentiation 44 (CD44), a stem cell marker, with the expression of other cancer-associated markers, including Raf kinase inhibitor protein (RKIP) and peroxiredoxin 2, in different pathological conditions of gastric cancer development using histological, immunohistological and western blot analyses. Initially, the murine model of gastric cancer was established using N-methyl-N-nitrosourea, a chemical carcinogen. Following initiation of cancer, immunohistochemistry was used to compare the expression of CD44, RKIP and peroxiredoxin 2 at different stages of cancer development. The results suggested CD44 and peroxiredoxin 2 expression was upregulated as the tumor progressed. However, expression of RKIP, a metastasis suppressor, was elevated in the initial stage of gastric cancer and suppressed during the aggressive stages. In agreement with previous data suggesting higher expressions of RKIP in the initial stages of cancer and its downregulation in the advanced stage, the results of the present study revealed that RKIP exhibited a negative effect on initial tumor development, and that the downregulation of RKIP in the advanced stages of cancer facilitated CD44 and peroxiredoxin 2 overexpression.

Phenol glycosides with in vitro anti-Helicobacter pylori activity from Hypericum erectum Thunb

To evaluate the anti-Helicobacter pylori activity of Hypericum erectum methanol extracts in order to provide the primary evidence for their use in clinical practice. An ethyl acetate fraction of H. erectum suspension-cell cultures inhibited the growth of H. pylori in vitro, with a MIC50 range of 38.7-63.2 μg/mL, comparable to metronidazole (MIC50  = 43.2 μg/mL). To further investigate the involved active compounds of the H. erectum extracts, four phenol glycosides were isolated for the current study: quercetin-3'-O-β-D-galactopyranoside, quercetin-3'-O-(2''-acetyl)-β-D-glucopyranoside, 4,6-dihydroxy-2-methoxyphenyl-1-O-β-D-glucopyranoside and 4-hydroxy-2,6-dimethoxyphenyl-1-O-α-L-rhamnopyranosyl(1-6)-β-D-glucopyranoside. The MIC50 values of 4,6-dihydroxy-2-methoxyphenyl-1-O-β-D-glucopyranoside and 4-hydroxy-2,6-dimethoxyphenyl-1-O-α-L-rhamnopyranosyl(1-6)-β-D-glucopyranoside from ATCC43504 strains were 7.3 and 27.3 μg/mL, respectively. The other two phenol glycosides did not show anti-H. pylori activity. The results of this work suggest that H. erectum has some therapeutic potential against H. pylori infection, which could be explored for patients with gastroduodenal disorders.