AimsThe pathophysiologies of nocturia (NOC) and nocturnal polyuria (NP) are multifactorial and their etiologies remain unclear in a large number of patients. Clock genes exist in most cells and organs, and the products of Clock regulate circadian rhythms as representative clock genes. Clock genes regulate lower urinary tract function, and a newly suggested concept is that abnormalities in clock genes cause lower urinary tract symptoms. In the present study, we investigated the voiding behavior of Clock mutant (Clock(19/19)) mice in order to determine the effects of clock genes on NOC/NP.
MethodsMale C57BL/6 mice aged 8-12 weeks (WT) and male C57BL/6 Clock(19/19) mice aged 8 weeks were used. They were bred under 12hr light/dark conditions for 2 weeks and voiding behavior was investigated by measuring water intake volume, urine volume, urine volume/void, and voiding frequency in metabolic cages in the dark and light periods.
ResultsNo significant differences were observed in behavior patterns between Clock(19/19) and WT mice. Clock(19/19) mice showed greater voiding frequencies and urine volumes during the sleep phase than WT mice. The diurnal change in urine volume/void between the dark and light periods in WT mice was absent in Clock(19/19) mice. Additionally, functional bladder capacity was significantly lower in Clock(19/19) mice than in WT mice.
ConclusionsWe demonstrated that Clock(19/19) mice showed the phenotype of NOC/NP. The Clock(19/19) mouse may be used as an animal model of NOC and NP. Neurourol. Urodynam. 36:1034-1038, 2017. (c) 2016 Wiley Periodicals, Inc.