Gastrointestinal motility and morphology in mice: Strain‐dependent differences

• Published in: Neurogastroenterology and motility 2020-06, Vol.32 (6), p.e13824-n/a
• Main Authors: Gama, Loyane Almeida, Rocha Machado, Mariana Pirani, Beckmann, Ana Paula Simões, Miranda, José Ricardo de Arruda, Corá, Luciana Aparecida, Américo, Madileine Francely
• Format: Article
• Language: English
• Subjects: BALB/c; C57BL/6; Contractility; duodenal contractility; Duodenum; Gastric motility; gastrointestinal transit; inbred; Morphology
• ISSN: 1350-1925; 1365-2982
• DOI: 10.1111/nmo.13824

Background BALB/c and C57BL/6 mice are widely used in biomedical research; however, the differences between strains are still underestimated. Our aims were to develop an experimental protocol to evaluate the duodenal contractility and gastrointestinal transit in mice using the Alternating Current Biosusceptometry (ACB) technique and to compare gastrointestinal motor function and morphology between BALB/c and C57BL/6 strains. Methods Male mice were used in experiments (a) duodenal contractility: animals which had a magnetic marker surgically fixed in the duodenum to determine the frequency and amplitude of contractions and (b) gastrointestinal transit: animals which ingested a magnetically marked chow to calculate the Oro‐Anal Transit Time (OATT) and the Fecal Pellet Elimination Rate (FPER). The animals were killed after the experiments for organ collection and morphometric analysis. Key Results BALB/c and C57BL/6 had two different duodenal frequencies (high and low) with similar amplitudes. After 10 hours of monitoring, BALB/c eliminated around 89% of the ingested marker and C57BL/6 eliminated 33%; OATT and FPER were slower for C57BL/6 compared with BALB/c. The OATT and amplitude of low frequency had a strong positive correlation in C57BL/6. For BALB/c, the gastric muscular layer was thicker compared to that measured for C57BL/6. Conclusions and Inferences The experimental protocol to evaluate duodenal contractility and fecal magnetic pellets output using the ACB technique in mice was successfully established. BALB/c strains had higher duodenal frequencies and a shorter time to eliminate the ingested marker. Our results showed differences in both motor function and gastrointestinal morphology between BALB/c and C57BL/6 strains. This study showed differences in duodenal contractility, gastrointestinal transit, and morphology among BALB/c and C57BL/6 mice strains evaluated in vivo. These results contribute to the choice of the most appropriate animal model for gastrointestinal physiology studies.