Changes in Anxiety-Related Behaviors, Voiding Patterns, and Urinary Bladder Contractile Properties in Male Mice Exposed to Water Avoidance Stress for 1 Day and 28 Days

Repeated water avoidance stress (WAS) for 10 days is a common rodent model to mimic the effect of chronic psychological stress on urinary bladder dysfunction. However, it remains obscure whether changes in the stress exposure period impact urinary bladder impairment differently. Therefore, this study aimed to investigate the effect of 1 (acute), 10 (chronic), and 28 (prolonged) days of WAS on anxiety-related behavior, voiding pattern, urinary bladder mast cells, and bladder contractility in C57BL/6J male mice. Mice exposed to 1 and 10 days of WAS showed decreased unsupported rearing. A decreased total void area after 1 and 10 days of the WAS was observed, which was reversed in the 28-day-WAS group. There was an increased number of degranulated mast cells in the bladder of the 10-day-WAS group. The 1-day WAS exposure enhanced tonic contractile response to a muscarinic agonist, carbachol, which was reversed by 5-HT₃ receptor antagonist pre-incubation. Interestingly, the 28-day WAS group showed a similar tonic contractile response to the control group. Our findings provide more insightful information about using 1-day WAS as an acute psychological stress model, and stress exposure longer than 10 days did not produce anxiety-like behavior and urinary bladder impairment.