Development of a BALB/c mouse model of Helicobacter pylori infection with fresh and frozen bacteria

Abstract

An experimental model for H. pylori infection was established by intragastrically challenging BALB/c mice with 1 ml (10 8 CFU/ml) of suspension for two consecutive days. Animals were divided into three groups. GA: mice inoculated with fresh bacteria; GB: mice inoculated with frozen bacteria, and GC: mice inoculated with brucella broth (control group). Animals were killed at 7, 14, 21, 28, 35 and 60 days pi and fragments of stomach and duodenum were collected, paraffin embedded and stained by hematoxylin-eosin and Giemsa. The results showed that challenged mice exhibited mild duodenitis and gastritis. In group GA, infiltration in the duodenum was lymphoplasmacytic until day 35; in group GB, it was lymphomonocytic for 60 days pi. In the stomach, H. pylori induced lymphomonocytic infiltration that was present from days 7 to 60 in group GA. In group GB, it was only present from days 14 to 35. In conclusion, our data suggested that freezing altered pathogenic properties of H. pylori and probably inhibited expression of bacterial antigens and consequently the establishment and maintenance of infection. Although the animals developed mild duodenitis and gastritis, the BALB/c mouse is not susceptible to developing peptic ulcers during H. pylori infection.

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

“…Although Ferrero et al 22 revealed that even a single inoculation of SS1 with 1.2 × 10 7 CFU/mL could colonize in 100% of mice stomachs, most of previous studies had inoculated H. pylori SS1 for 3 times at 2 days intervals. 14 , 15 , 19 – 21 However in the present study we tried to inoculate H. pylori 4 or 5 times to enhance bacterial colonization and 5 times inoculation produced higher bacterial density than 3 or 4 times inoculation and the culture rate was more than 90% when inoculated 5 times. To prove successful infection, H. pylori culture from the scratched mice stomach was performed in this study and satisfactory amounts of colonies were founded.…”

“… 18 In fact, a previous study revealed that although BALB/c mice develop mild duodenitis and gastritis during H. pylori infection, they are not susceptible to developing peptic ulcers. 19 When H. pylori SS1 was inoculated in BALB/c mice, only 5% of bacteria was colonized in antrum and the BALB/c mice developed chronic gastritis or atrophy less frequently than the C57BL/6 mice. 4 Therefore, the C57BL/6 mice seem to be more suitable as an H. pylori animal model, with a high colonization rate and similar pathological results as in human gastric experiments.…”

Comparative analysis of two-dimensional electrophoresis maps (2-DE) of Helicobacter pylori from Brazilian patients with chronic gastritis and duodenal ulcer: a preliminary report

“…pylori strains were isolated from gastric mucosa biopsies of two patients who had not been previously treated, submitted to upper gastrointestinal endoscopy at Gastrocentro, UNICAMP. Bacterial isolation and protein extraction were performed according to our previous reports 6,8 .…”

“…pylori strains were isolated from gastric mucosa biopsies of two patients who had not been previously treated, submitted to upper gastrointestinal endoscopy at Gastrocentro, UNICAMP. Bacterial isolation and protein extraction were performed according to our previous reports 6,8 .The samples were submitted to isoelectrofocusing (IEF) solubilized with 8M urea, 4% CHAPS, 70 mM DTT, ampholine linear pH gradient 4-7 (pH 4-7L) 1.5% and 0.001% bromophenol blue. At this stage, 64 μg of each protein sample were applied to polyacrylamide dried strips, pH gradient 4-7 L (immobilized pH gradient -IPG).…”