Basic Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Pathophysiol. Jun 20, 2020; 11(4): 84-103
Published online Jun 20, 2020. doi: 10.4291/wjgp.v11.i4.84
P2X7 receptor antagonist recovers ileum myenteric neurons after experimental ulcerative colitis
Roberta Figueiroa Souza, Mariá Munhoz Evangelinellis, Cristina Eusébio Mendes, Marta Righetti, Múcio Cevulla Silva Lourenço, Patricia Castelucci
Roberta Figueiroa Souza, Cristina Eusébio Mendes, Marta Righetti, Múcio Cevulla Silva Lourenço, Patricia Castelucci, Department of Anatomy, University of São Paulo, São Paulo 05508-900, Brazil
Mariá Munhoz Evangelinellis, Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-900, Brazil
Author contributions: Souza RF performed the immunohistochemistry experiments and analyzed the results; Evangelinellis MM and Mendes CE helped with inflammation and BBG protocols; Righetti M and Lourenço MCS performed the histological protocols; Castelucci P planned experiments, analyzed the results, and wrote and edited the manuscript.
Supported by Foundation São Paulo Research, No. 2014/25927-2 and No. 2018/07862-1; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; and Conselho Nacional de Desenvolvimento Científico e Tecnológico.
Institutional animal care and use committee statement: This study was approved by the Institute of Biomedical and Sciences/an Faculty of Veterinary Medicine and Animal Science, University of São Paulo, Protocol number # 1793240815. The animal experiments in this study were conducted according to the current regulations of the Ethics Committee on Animal Use of the Biomedical Science Institute of the University of São Paulo. Furthermore, all protocols were approved by the Ethics Committee on Animal Use of the Biomedical Science Institute of the University of São Paulo (Protocol 68/2016).
Conflict-of-interest statement: The authors have no conflicts of interest.
Data sharing statement: No additional data are available.
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Patricia Castelucci, PhD, Associate Professor, Department of Anatomy, University of São Paulo, Lineu Prestes, 2415, São Paulo 05508-900, Brazil. pcastel@usp.br
Received: January 7, 2020
Peer-review started: January 7, 2020
First decision: February 19, 2020
Revised: April 4, 2020
Accepted: April 18, 2020
Article in press: April 18, 2020
Published online: June 20, 2020
Abstract
BACKGROUND

The P2X7 receptor is expressed by enteric neurons and enteric glial cells. Studies have demonstrated that administration of a P2X7 receptor antagonist, brilliant blue G (BBG), prevents neuronal loss.

AIM

To report the effects of BBG in ileum enteric neurons immunoreactive (ir) following experimental ulcerative colitis in Rattus norvegicus albinus.

METHODS

2,4,6-trinitrobenzene sulfonic acid (TNBS group, n = 5) was injected into the distal colon. BBG (50 mg/kg, BBG group, n = 5) or vehicle (sham group, n = 5) was given subcutaneously 1 h after TNBS. The animals were euthanized after 24 h, and the ileum was removed. Immunohistochemistry was performed on the myenteric plexus to evaluate immunoreactivity for P2X7 receptor, neuronal nitric oxide synthase (nNOS), choline acetyltransferase (ChAT), HuC/D and glial fibrillary acidic protein.

RESULTS

The numbers of nNOS-, ChAT-, HuC/D-ir neurons and glial fibrillary acidic protein-ir glial cells were decreased in the TNBS group and recovered in the BBG group. The neuronal profile area (μm2) demonstrated that nNOS-ir neurons decreased in the TNBS group and recovered in the BBG group. There were no differences in the profile areas of ChAT- and HuC/D-ir neurons.

CONCLUSION

Our data conclude that ileum myenteric neurons and glial cells were affected by ulcerative colitis and that treatment with BBG had a neuroprotective effect. Thus, these results demonstrate that the P2X7 receptor may be an important target in therapeutic strategies.

Keywords: P2X7 receptor, Brilliant blue G, Myenteric plexus, Experimental ulcerative colitis, Ileum, Chemical coding

Core tip: This work aims to analyze the effects of experimental ulcerative colitis (EUC) in ileum myenteric neurons immunoreactive (ir) for P2X7 receptor, neuronal nitric oxide synthase, choline acetyltransferase, HuC/D and enteric glial cells immunoreactive for glial fibrillary acidic protein. The animals were treated with P2X7 receptor antagonist, brilliant blue G (BBG). The results showed that the numbers of neuronal nitric oxide synthase-, choline acetyltransferase-, HuC/D-ir neurons and glial fibrillary acidic protein-ir glial cells were decreased in the EUC group and recovered in the animals treated with BBG. BBG treatment demonstrated that the P2X7 receptor may be a possible therapeutic target in the treatment of the EUC.