No Correlation of Inflammation With Colonization of Helicobacter pylori in the Stomach of Mice Fed High-salt Diet

Abstract

Background:Previous studies on Helicobacter pylori infection in mice have contributed to better understanding of the pathogenesis of chronic gastritis and gastric carcinoma. The aim of this study was to evaluate H. pylori colonization and subsequent inflammatory responses in the stomachs of C57BL/6 mice depending on inoculation number and the presence of high-salt diet.Methods:Eighty-four female mice with 4 weeks age were used in this study. The infected mice were gavaged with H. pylori strain Sydney-1 (SS1), and the uninfected mice were dosed with vehicle. In each of these groups, half of the mice were fed ona basal diet (0.25% salt) and the other half were fed on a high-salt diet (7.5% salt). The infected mice were inoculated 4 or 5 times, and infection status and degree of inflammation were checked by culture and histopathology, respectively, after 4 weeks. Gastric mucosal myeloperoxidase and tumor necrosis factor-alpha were measured by ELISA.Results:The overall infection rate was 95.2%; the infection rate after 5 inoculations (100%) was greater than that after 4 inoculations (91.3%). However, no differences in the degree of inflammation were found between 2 groups. The bacterial density was also significantly increased in mice that were on the high-salt diet and had been inoculated 5 times, respectively. Mean neutrophil infiltration in the infected group was 1.7±0.6 (1, minimal; 2, mild; 3, moderate; 4, marked). However, the high-salt diet was not increase the inflammatory grade in the infected group. Gastric mucosal myeloperoxidase and tumor necrosis factor-alpha levels did not increased by the high-salt diet and increased the number of inoculation.Conclusions:In spite of well colonization of H. pylori in the stomachs of C57BL/6 mice, the degree of subsequent inflammation was irrelevant to high-salt diet and frequent (5 times) inoculations.

Histologic Findings and Inflammatory Reactions After Long-term Colonization of Helicobacter felis in C57BL/6 Mice

“… 17 , 21 We previously reported about H. pylori SS1 infection in C57BL/6 mice with minimal to mild (score 1–2) neutrophil infiltration 4 weeks after inoculation. 22 Furthermore, the mean gastric mucosal MPO level was 3.4 ± 0.6 ng/mL at 4 weeks after H. pylori infection. 22 In the present study, H. felis infection resulted in mild to moderate neutrophil infiltration (score 2–3) during the same period, and one infected mice showed high-grade dysplasia 4 weeks after inoculation.…”

Reversibility of atrophic gastritis and intestinal metaplasia after Helicobacter pylori eradication ‐ a prospective study for up to 10 years

“…Third, Rugge M, et al have reported that there is an interobserver inconsistency for 2558 subjects (mean age 57.6 years; 1506 men and 1052 women). In one study, inadequate (not applicable) atrophic gastritis rate for the assessment was 27.8% in the antrum and 21.8% in the corpus due to several problems such as inadequate orientation at the stage of fixation or dense inflammation . To avoid such limitation, only one pathologist (H.S.L) observed biopsy specimen to diagnose and grade AG and IM.…”

The prevalence of histologic atrophy and intestinal metaplasia in the corpus has decreased over 15 years in females in the Korean population

“…Second, the inadequate (not applicable) atrophy rate for the assessment was rather high, 31.2% (624/2002) in antrum and 25.1% (503/2002) in the corpus, which might originate from several problems, such as inadequate orientation at the stage of fixation or dense inflammation. 58 To avoid such limitations, only one pathologist (HSL) investigated biopsy specimens to diagnose and grade atrophy and IM. In addition, we enrolled a relatively large number of subjects over 15 years.…”