Effects of Oxytocin on Rats With Stress-Induced Increased Urinary Frequency

Urinary frequency and bladder hypersensitivity are among the lower urinary tract symptoms exacerbated by psychological stress. This study investigated whether chronic oxytocin (OXT) administration could alleviate stress-induced bladder dysfunction and modulate central stress pathways.

Female Sprague-Dawley rats were allocated to control, stress, or stress/OXT groups (n=14 per group) and exposed to repeated variable stress (RVS) for 1 week. Assessments included mechanical sensitivity, cystometric parameters, plasma catecholamine and cortisol levels, bladder histology, c-Fos expression in the paraventricular nucleus (PVN), and gene expression in bladder and brain regions.

RVS induced mechanical hypersensitivity, reduced intercontraction intervals, increased bladder weight, and raised plasma adrenaline, dopamine, and cortisol levels. The bladder also showed epithelial thickening, submucosal nerve hyperplasia, and increased prostaglandin E receptor 3 and epithelial sodium channel expression. Stress significantly enhanced PVN activation and increased brainstem expression of choline acetyltransferase, corticotropin-releasing factor, and tyrosine hydroxylase. With OXT treatment, intercontraction intervals normalized, catecholamine and cortisol levels declined, PVN c-Fos activation decreased, and OXT receptor expression increased in the brainstem, hypothalamus, and thalamus, and glutamate decarboxylase 1 expression increased in the hypothalamus and thalamus. Interleukin-6 expression decreased with OXT treatment but did not change in response to stress.

Chronic OXT administration was associated with improved stress-induced urinary frequency and modulation of central stress pathways; evidence of direct peripheral anti-inflammatory effects was limited.