Alternate-day fasting induces metabolic and morphofunctional changes in the gastrointestinal tract of male rats.

Alternate-day fasting (ADF) is a nutritional intervention with modulatory and overall protective effects, but its role in the gastrointestinal (GI) tract is still uncertain. The aim of this study was to investigate the influence of ADF on the metabolic patterns and morphofunctional motility of the GI tract in rats. Thirty-two male Wistar rats were allocated into groups: control for 15 days (CON 15, n = 8), control for 30 days (CON 30, n = 8), ADF for 15 days (ADF 15, n = 8), and ADF for 30 days (ADF 30, n = 8). Blood glucose, body weight, and food and water consumption were measured. Frequency and amplitude of gastric contractions as well as gastric emptying time, small intestinal transit time, and cecum arrival time were measured. Intestinal histomorphometric, relative weight of organs, lipidogram, and leptin levels were also evaluated. ADF decreased water consumption and food consumption. The weight gain decreased; however, the relative kidney weight increased. ADF triggered an increase in the amplitude of gastric contractions and accelerated gastric emptying. However, small intestinal transit time was delayed in both ADF groups. Total cholesterol, triglycerides, non-HDL cholesterol, and very low-density lipoprotein cholesterol levels decreased, whereas villus height, depth of the crypts and thickness of the circular, and longitudinal muscular layers of intestine increased after ADF. In conclusion, our results showed ADF exert an effect on both metabolism and GI motility and impacts on overall digestive functions.

BALB/c and C57BL/6 mouse strains influence gastric function outcomes with administration of cisplatin and dexamethasone

Abstract Our aim was to evaluate the effects of cisplatin and dexamethasone alone and combined on gastric contractility and histomorphometry of BALB/c and C57BL/6 mice. BALB/c and C57BL/6 male mice (8-week-old) were randomly separated into: Control; Cisplatin (7.5 mg/Kg); Dexamethasone (2.0 mg/Kg); and Dexamethasone plus Cisplatin (2.0 mg/Kg of dexamethasone 1-hour prior to 7.5 mg/Kg of cisplatin). Drugs were administered intraperitoneally for three days. Body weight and food intake were evaluated on 2nd day. Alternating Current Biosusceptometry technique was employed to measure gastric contractions on 3rd day. Afterward, mice were killed for gastric histomorphometric analysis. Cisplatin decreased food intake and caused bradygastria in BALB/c mice; however, the amplitude of gastric contractions decreased in both BALB/c and C57BL/6. Dexamethasone and cisplatin combined restored the gastric frequency and food intake only in BALB/c, but drug combination reduced the gastric amplitude of contractions in both strains. Dexamethasone alone increased gastric mucosa thickness in C57BL/6 and decreased muscular thickness in BALB/c. In conclusion, the mouse strains presented differences in acute effects of cisplatin and dexamethasone alone and combined on gastric function. This reinforces the importance of choosing the appropriate mouse strain for studying the acute effects of drugs on the gastrointestinal tract.

Gastrointestinal motility and morphology in mice: Strain-dependent differences.

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.