Bladder Hyperactivity Induced by Chronic Variable Stress in Rats

ObjectivesTo investigate the effect of chronic stress on bladder function. We used awake cystometry and investigated the expressions of contractile-associated proteins. MethodsSixteen adult female Sprague-Dawley rats, weighing approximately 220g, were randomly assigned and divided into control (CON, n=8) and chronic variable stress (CVS, n=7) groups. The rats of the CVS group spent 6weeks under the CVS protocol. After 6weeks, continuous filling cystometry was performed on conscious animals. The basal pressure, maximal pressure, micturition duration, threshold pressure, micturition interval and micturition volume were measured in each rat. After measuring cystometric parameters, the rat was sacrificed. Western blotting of the entire urinary bladder was performed for detecting the changes in contractile-associated protein expression. ResultsCompared to the control group, basal pressure and threshold pressure were significantly higher (P<0.05) while micturition duration, micturition interval and micturition volume were significantly lower in the CVS group (P<0.05). In the western blot study, neuronal nitric oxide synthase (nNOS) expression was weaker and RhoA/Rho-kinase alpha were stronger in the CVS group than those in the CON group. ConclusionsThese results suggest that chronic variable stress induces changes in bladder function lead to bladder hyperactivity and possibly related to the changes in RhoA/Rho-kinase and nNOS.