Emotional versus physical stress in mice: Impact on bladder function

Eliza West, Donna J Sellers, Russ Chess-Williams, Catherine McDermott*

*Corresponding author for this work

Research output: Contribution to journalMeeting AbstractResearchpeer-review

Abstract

Introduction: A body of clinical evidence has linked psychological stress with bladder disorders. Many of these bladder disorders have been associated with voiding dysfunction, particularly in people with a history of abuse. Stress appears to cause or worsen symptoms of bladder dysfunction. Despite this strong clinical link between psychological stress and bladder dysfunction, there is little understanding of the mechanism contributing to voiding changes. The aim of this study was to determine the effects of social defeat (physical stress) or witness trauma (emotional stress) on voiding behaviour and mechanisms controlling bladder function in mice. Materials & methods: A model of physical and emotional stress (social defeat and witness trauma respectively) was used. Male ARC1 mice were screened for aggressive behaviour and housed individually. Male C57Bl/6J mice (12-14 weeks) were housed in pairs for three days prior to and during the 10-day stress protocol, each randomly allocated to either, Group 1 social defeat or Group 2 witness trauma group. The male C57Bl/6J pairs were placed in a plexiglass chamber with the aggressor mouse for 1 hour/day for 10 days. The social defeat and aggressor mouse were in physical contact for 5 minutes and separated by a transparent perforated barrier for 55 minutes. The witness mouse was physically separated but could observe the interaction between the two mice. Voiding pattern analysis was conducted on days 0, 1, 3, 7 and 10. Twenty-four hours after final stress exposure, mice were euthanised and a blood sample taken to analyse corticosterone levels. Bladders were removed, catheterised and intravesical pressure responses recorded during distension and in response to stimulation of purinergic and cholinergic agonists, and following electrical field stimulation2. AREC: BOND/536/17, Bond University. Results: Plasma corticosterone levels were significantly increased following 10-days of social defeat or witness trauma stress when compared to unstressed controls (p<0.001) (Fig. 1A). There was a significant increase in average void size in the social defeat group from day 3 (Fig. 1B), with no significant change in total voided volume, indicating an altered voiding phenotype. Witness trauma did not alter voiding behaviour at any timepoint tested. Spontaneous contractility of bladders, and bladder contractions to muscarinic and purinergic agonists were unchanged. However, nerve evoked contractile responses to electric field stimulation (EFS) were significantly increased at all frequencies in bladders from social defeat but not witness trauma mice (Fig. 1C). Conclusion: Exposure to physical or emotional stress produces a similar hormonal stress response in both models of psychological stress. However, changes in voiding behaviour and local functional changes in the bladder are dependent on the type of stressor. The increase in average void size observed in the social defeat group is consistent with previous reports of urine retention in this model. The increase in contractility to EFS may indicate local changes in efferent innervation rather than detrusor contractility. This study reports a male model of social defeat with reduced urinary frequency, with no voiding changes observed in the witness
Original languageEnglish
Pages (from-to)95-96
Number of pages2
JournalAustralian and New Zealand Continence Journal
Volume25
Issue number4
Publication statusPublished - 2019
Event28th National Conference on Incontinence - Pullman Melbourne Albert Park, Melbourne, Australia
Duration: 13 Nov 201916 Nov 2019
Conference number: 28th
https://www.ncoi.org.au/

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