Determination of gastric emptying in nonobese diabetic mice

Animal studies on diabetic gastroparesis are limited by inability to follow gastric emptying changes in the same mouse. The study aim was to validate a nonlethal gastric emptying method in nonobese diabetic (NOD) LtJ mice, a model of type 1 diabetes, and study sequential changes with age and early diabetic status. The reliability and responsiveness of a [¹³C]octanoic acid breath test in NOD LtJ mice was tested, and the test was used to measure solid gastric emptying in NOD LtJ mice and nonobese diabetes resistant (NOR) LtJ mice. The ¹³C breath test produced results similar to postmortem recovery of a meal. Bethanechol accelerated gastric emptying [control: 92 ± 9 min; bethanechol: 53 ± 3 min, mean half emptying time (T_1/2) ± SE], and atropine slowed gastric emptying (control: 92 ± 9 min; atropine: 184 ± 31 min, mean T_1/2 ± SE). Normal gastric emptying (T_1/2) in nondiabetic NOD LtJ mice (8-12 wk) was 91 ± 2 min. Aging had differing effects on gastric emptying in NOD LtJ and NOR LtJ mice. Onset of diabetes was accompanied by accelerated gastric emptying during weeks 1-2 of diabetes. Gastric emptying returned to normal by weeks 3-5 with no delay. The [¹³C]octanoic acid breath test accurately measures gastric emptying in NOD LtJ mice, is useful to study the time course of changes in gastric emptying in diabetic NOD LtJ mice, and is able to detect acceleration in gastric emptying early in diabetes. Opposing changes in gastric emptying between NOD LtJ and NOR LtJ mice suggest that NOR LtJ mice are not good controls for the study of gastric emptying in NOD LtJ mice.