Role of ¹³C-Urea Breath Test in Experimental Model of Helicobacter pylori Infection in Mice

Background: Animal models have been widely used to study Helicobacter pylori infection. Evaluation of H. pylori infection status following experimental inoculation of mice usually requires euthanasia. The ¹³C-urea breath test ( ¹³C-UBT) is both sensitive and specific for detection of H. pylori in humans. Thus, it would be very useful to have such a test with the same accuracy for the follow-up of this infection in animal models of gastric infection. Accordingly, the purpose of this study was to develop and evaluate a ¹³C-UBT method for following the course of H. pylori infection in a mouse model. Material and Methods: A total of 50 female C57BL/6 mice were gavaged three times with either 10 ⁸ colony-forming units of H. pylori (n=29) or saline solution only (n=21). After 2months of infection, mice were fasted for 14hours and ¹³C-UBT was performed using 300μg of ¹³C-urea. The mice were killed, and the stomach was removed and processed for immunohistochemistry and PCR. Results: The optimal time for breath sample collection in mice was found to be 15minutes. The ¹³C-UBT cutoff was set at 3.0‰δPDB. Using PCR as the gold standard, the sensitivity of ¹³C-UBT and immunohistochemistry was 96.6 and 72.4%, respectively, while the specificity was 85.7 and 95.2%, respectively. Conclusions: ¹³C-UBT was shown to be a reliable method for the detection of H. pylori infection in C57BL/6 mice and was even more accurate than immunohistochemistry. The use of ¹³C-UBT in the mouse model of H. pylori infection can be very useful to detect the bacterium without the need to kill the animals in long-term time course studies.