The purposes of this study were to investigate the effect of detrusor overactivity induced by partial bladder outlet obstruction (BOO) on the expression of transient receptor potential vanilloid-4 (TRPV4) in rat urinary bladder, and to determine the role of these molecules in the detrusor overactivity.
Female Sprague-Dawley rats were divided into control (n=30) and experimental (n=30) groups. The BOO group underwent partial BOO. The control group underwent a sham operation. After 4 weeks, a urodynamic study was performed to measure the contraction interval and contraction pressure. The expression and cellular localization of TRPV4 was determined by Western blot and immunofluorescent study in rat urinary bladder.
In cystometrograms, the contraction interval (min) was significantly lower in the BOO group (3.1 ± 1.2) than in the control group (6.9 ± 0.9) (p<0.05). Conversely, the average contraction pressure (mmHg) was significantly higher in the BOO group (20.1 ± 3.5) than in the control group (12.1 ± 2.1) (p<0.05). TRPV4 was expressed mainly in the cytoplasm of the urothelium. The TRPV4 protein expressions were significantly increased in the BOO rats (p<0.05).
Detrusor overactivity induced by BOO causes a significant increase in the expression of TRPV4. This finding may imply that TRPV4 might be closely related to the bladder signal activity and may have a functional role in detrusor overactivity that occurs in association with BOO.