Basic Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 28, 2022; 28(48): 6935-6949
Published online Dec 28, 2022. doi: 10.3748/wjg.v28.i48.6935
Bladder-colon chronic cross-sensitization involves neuro-glial pathways in male mice
Karim Atmani, Fabien Wuestenberghs, Maximilien Baron, Illona Bouleté, Charlène Guérin, Wafa Bahlouli, David Vaudry, Jean Claude do Rego, Jean-Nicolas Cornu, Anne-Marie Leroi, Moïse Coëffier, Mathieu Meleine, Guillaume Gourcerol
Karim Atmani, Fabien Wuestenberghs, Maximilien Baron, Illona Bouleté, Charlène Guérin, Wafa Bahlouli, David Vaudry, Jean-Nicolas Cornu, Anne-Marie Leroi, Moïse Coëffier, Mathieu Meleine, Guillaume Gourcerol, Nutrition, Gut and Brain Unit (Inserm U1073), Institute for Research and Innovation in Biomedicine, Université de Rouen Normandie, Rouen 76000, France
Fabien Wuestenberghs, Department of Gastroenterology and Hepatology, Université Catholique de Louvain, CHU UCL Namur, Yvoir 5530, Belgium
Fabien Wuestenberghs, Anne-Marie Leroi, Guillaume Gourcerol, Department of Physiology, CHU Rouen, Université de Rouen Normandie, Rouen 76031, France
Maximilien Baron, Jean-Nicolas Cornu, Department of Urology, CHU Rouen, Université de Rouen Normandie, Rouen 76000, France
David Vaudry, Inserm, UMR 1245, Team Epigenetics and Pathophysiology of Neuro-developmental Disorders, Université de Rouen Normandie, Rouen 76000, France
Jean Claude do Rego, Behavioural Analysis Platform (SCAC), HeRacLeS Inserm US51-CNRS UAR2026, Institute for Research and Innovation in Biomedicine, Université de Rouen Normandie, Rouen 76000, France
Moïse Coëffier, Department of Nutrition, CHU Rouen, Université de Rouen Normandie, Rouen 76000, France
Mathieu Meleine, Inserm U1107, NeuroDol, Clermont Auvergne University, Clermont-Ferrand 63000, France
Author contributions: Gourcerol G and Leroi AM designed the research study; Atmani K, Meleine Mathieu, Baron M, Bouleté I, Guérin C, Vaudry D, do Rego JC and Bahlouli W performed the research; Atmani K, Wuestenberghs F, Meleine M and Gourcerol G analyzed the data; Atmani K, Wuestenberghs F and Gourcerol G drafted the manuscript; Atmani K, Wuestenberghs F, Baron M, Bouleté I, Guérin C, Bahlouli W, Vaudry D, do Rego JC, Cornu JN, Leroi AM, Coëffier M, Meleine M and Gourcerol G critically reviewed the manuscript for important intellectual content; All authors approved the final version of the article, including the authorship list; Gourcerol G accepts official responsibility for the overall integrity of the manuscript.
Institutional animal care and use committee statement: All animal experiments conformed to the internationally accepted principles for the care and use of laboratory animals, and the protocol was approved by the local Ethics Committee for Animal Experiments (CENOMEXA No: N/02-01-13/02/01-16).
Conflict-of-interest statement: None of the authors have any conflicts of interest.
Data sharing statement: No additional data is 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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Guillaume Gourcerol, MD, PhD, Chief Doctor, Professor, Department of Physiology, CHU Rouen, Université de Rouen Normandie, 1 Rue de Germont, Rouen 76031, France. guillaume.gourcerol@chu-rouen.fr
Received: May 18, 2022
Peer-review started: May 18, 2022
First decision: August 1, 2022
Revised: October 2, 2022
Accepted: October 26, 2022
Article in press: October 26, 2022
Published online: December 28, 2022
Abstract
BACKGROUND

Irritable bowel syndrome and bladder pain syndrome often overlap and are both characterized by visceral hypersensitivity. Since pelvic organs share common sensory pathways, it is likely that those syndromes involve a cross-sensitization of the bladder and the colon. The precise pathophysiology remains poorly understood.

AIM

To develop a model of chronic bladder-colon cross-sensitization and to investigate the mech-anisms involved.

METHODS

Chronic cross-organ visceral sensitization was obtained in C57BL/6 mice using ultrasound-guided intravesical injections of acetic acid under brief isoflurane anesthesia. Colorectal sensitivity was assessed in conscious mice by measuring intracolonic pressure during isobaric colorectal distensions. Myeloperoxidase, used as a marker of colorectal inflammation, was measured in the colon, and colorectal permeability was measured using chambers. c-Fos protein expression, used as a marker of neuronal activation, was assessed in the spinal cord (L6-S1 level) using immunohistochemistry. Green fluorescent protein on the fractalkine receptor-positive mice were used to identify and count microglia cells in the L6-S1 dorsal horn of the spinal cord. The expression of NK1 receptors and MAPK-p38 were quantified in the spinal cord using western blot.

RESULTS

Visceral hypersensitivity to colorectal distension was observed after the intravesical injection of acetic acid vs saline (P < 0.0001). This effect started 1 h post-injection and lasted up to 7 d post-injection. No increased permeability or inflammation was shown in the bladder or colon 7 d post-injection. Visceral hypersensitivity was associated with the increased expression of c-Fos protein in the spinal cord (P < 0.0001). In green fluorescent protein on the fractalkine receptor-positive mice, intravesical acetic acid injection resulted in an increased number of microglia cells in the L6-S1 dorsal horn of the spinal cord (P < 0.0001). NK1 receptor and MAPK-p38 levels were increased in the spinal cord up to 7 d after injection (P = 0.007 and 0.023 respectively). Colorectal sensitization was prevented by intrathecal or intracerebroventricular injections of minocycline, a microglia inhibitor, by intracerebroventricular injection of CP-99994 dihydrochloride, a NK1 antagonist, and by intracerebroventricular injection of SB203580, a MAPK-p38 inhibitor.

CONCLUSION

We describe a new model of cross-organ visceral sensitization between the bladder and the colon in mice. Intravesical injections of acetic acid induced a long-lasting colorectal hypersensitivity to distension, mediated by neuroglial interactions, MAPK-p38 phosphorylation and the NK1 receptor.

Keywords: Cross-organ sensitization, MAPK-p38, Microglia, NK1 receptor, Pain, Visceral hypersensitivity

Core Tip: A model of chronic cross-organ visceral sensitization in mice was developed using ultrasound-guided intravesical injections of acetic acid. Visceral hypersensitivity to colorectal distension was observed as early as 1 h post-injection and lasted up to 7 d. Visceral hypersensitivity was associated with an increased expression of c-Fos protein in the spinal cord. The NK1 receptor and MAPK-p38 levels were upregulated in the spinal cord 7 d post-injection. Colorectal sensitization was prevented by intrathecal or intracerebroventricular injections of minocycline, a microglia inhibitor, by intracerebroventricular injection of CP-99994, a NK1 antagonist, and by intracerebroventricular injection of SB203580, a MAPK-p38 inhibitor.