Background: Noninvasive breath tests may have significant utility for the measurement of gastric emptying in mice, but the tests' sensitivity for detection of changes in gastric emptying has not been evaluated.
Materials and methods: Hydroxypropyl methyl cellulose was incorporated into a liquid meal to delay gastric emptying, and mice were injected with erythromycin to accelerate emptying of a liquid or solid meal. All test meals were labelled with (13)C-acetic acid or (13)C-octanoic acid. Breath samples collected at intervals were analysed for (13)CO(2) content, and gastric emptying rates were calculated from the resultant (13)CO(2) excretion curves.
Results: As predicted, hydroxypropyl methyl cellulose slowed emptying compared with water (14.21 +/- 0.94 min vs. 9.17 +/- 0.47 min, P < 0.001), while erythromycin treatment accelerated emptying of liquids (10.96 +/- 0.78 min vs. 16.41 +/- 1.94 min, P < 0.05) and solids (108.81 +/- 18.06 vs. 157.95 +/- 12.01 min, P < 0.05) compared with the saline injected controls.
Conclusions: These data indicate that in mice the breath test is sensitive enough to detect differences in gastric emptying induced by meal composition and pharmacological agents. Noninvasive measurement of gastric emptying in mice will be useful as a method to evaluate the effect of nutrients or drugs on the motility of the gastrointestinal tract.