Characterizing Colonic Migrating Motor Complexes (CMMCs) Using a Novel Method in Ex Vivo Mouse Colon
*John R. Konen1,2, *Emily J. Joyce2, *Colleen B. Kerrigan1,2, *Gary M. Mawe2, *Grant W. Hennig2
1Department of Surgery, The University of Vermont Medical Center, Burlington, VT; 2Department of Neurological Sciences, University of Vermont, Burlington, VT
Objective: Alterations in the enteric nervous system (ENS) play an important role in regulating gastrointestinal (GI) motility. It is well known that changes in the ENS occur with various GI disorders. The colonic migrating motor complex (CMMC) is a rhythmic propagating contractile event that is spontaneously generated by the ENS. It has a central role in colonic fecal propulsion. A novel technique to analyze changes in CMMCs in an ex vivo model of mouse colon is described.
Design: Non-randomized control experiment
Setting: Laboratory
Patients: C57BL/6 mice (7-15 week-old)
Interventions: Mice were given various pharmacological agents or vehicle in vivo by enema and euthanized at 30 minutes. Following euthanasia, the whole colon was dissected out and pinned in a physiologic bath. High-resolution videos of the colon were performed and spatiotemporal maps were generated using custom software.
Main Outcome Measures: Spatiotemporal maps were analyzed to evaluate and compare gut diameter, CMMC frequency, length, direction, velocity, amplitude, and initiation sites between vehicle and treated mice.
Results: Neurogenic (CMMCs) and myogenic (ripples) mediated motor patterns were observed along the entire length of the colon. Pharmacologically-treated colons showed altered strength, prevalence and type of motor patterns.
Conclusions: These results demonstrate a novel and physiologic method to assess changes in motor behaviors in whole murine colon. It allows for further characterization of potential therapeutic targets within the GI tract, and assessment of motility patterns in various disease states or transgenic models.
