Brazil Nut (Bertholletia excelsa H.B.K) Retards Gastric Emptying and Modulates Enteric Glial Cells in a Dose-Dependent Manner

Abstract

Background

The role of food and nutrients in the regulation of enteric glial cell functions is unclear. Some foods influence enteric neurophysiology and can affect glial cell functions that include regulation of the intestinal barrier, gastric emptying, and colonic transit. Brazil nuts are the most abundant natural source of selenium, unsaturated fatty acids, fibers, and polyphenols.

Objective

The study investigated the effects of a Brazil nut-enriched diet on enteric glial cells and gastrointestinal transit.

Methods

Two-month-old male Wistar rats were randomized to a standard diet (control group, CG), standard diet containing 5% (wt/wt) Brazil nut (BN5), and standard diet containing 10% (wt/wt) Brazil nut (BN10) (n = 9 per group). After eight weeks, the animals underwent constipation and gastric emptying tests to assess motility. Evaluations of colonic immunofluorescence staining for glial fibrillary acidic protein (GFAP) and myenteric ganglia area were performed.

Results

The BN5 group showed increased weight gain while the BN10 group did not (p < 0.0001). The BN10 group showed higher gastric residue amounts compared to the other groups (p = 0.0008). The colon exhibited an increase in GFAP immunoreactivity in the BN5 group compared to that in the other groups (p = 0.0016), and the BN10 group presented minor immunoreactivity compared to the CG (p = 0.04). The BN10 group presented a minor ganglia area compared to the CG (p = 0.0155).

Conclusion

The Brazil nut-enriched diet modified the gastric residual, colonic GFAP immunoreactivity, and myenteric ganglia area after eight weeks in healthy male Wistar rats.

Keywords:

• Brazil nut
• enteric glia
• enteric glial cells
• glial fibrillary acid protein
• enteric ganglia

Acknowledgments

We are thankful to the Experimental Nutrition Laboratory (LabNe) – Fluminense Federal University for technical assistance and use of the animal house, Laboratory of Nutrition and Functional Assessment (LANUFF) – Fluminense Federal University for technical assistance and use of DXA equipment and Agropecuária Aruanã for the donation of Brazil nuts.

Disclosure statement

The authors declare that there no conflict of interest.

Ethics approval

This protocol was approved by the Fluminense Federal University’s Ethical Committee on Animal Research, Niterói-RJ, Brazil (protocol 956/2017).

Additional information

Funding

This project and scholarships were supported by the following Brazilian foundations: The State of Rio de Janeiro Carlos Chagas Filho Research Foundation (FAPERJ) (Process E-26/203.269/2017), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) – Finance Code 001 and National Counsel of Technological and Scientific Development (CNPq).