Decreased urothelial expression of caveolin 1 and 2 in aging rats showing detrusor overactivity: Potential association with aging bladder

Purpose: The purpose of this study was to investigate the effect of aging on bladder function and caveolin protein expression in rat urothelium. Materials and Methods: Female Sprague-Dawley rats were divided into the following two groups: young age control group (12 weeks) and old-aged group of rats (80 weeks). Urodynamic measurements were taken to compare the contraction interval and the contraction pressure between the two groups. The expression and cellular localization of caveolin 1 and 2 in the urothelium of the rat urinary bladder were determined by Western blot and immunofluorescence microscopy. Results: In cystometrograms, the contraction interval (min) was significantly shorter in the old-aged group (3.7 +/- 0.5 min) than in the young age control group (6.2 +/- 0.8 min). Also, the average contraction pressure (mmHg) was lower in the old-aged group (8.4 +/- 0.6 mmHg) than in the young age control group (13.2 +/- 1.3 mmHg). Caveolin 1 and 2 were expressed in the subepithelial area in the urothelium. The protein expression of both caveolin 1 and 2 was significantly lower in the old-aged group than in the young age control group. Conclusions: Aging caused a significant change in the expression of caveolin 1 and 2 in the urothelium of the rat urinary bladder. These findings suggest that these molecules might have specific roles in the functional change of the urinary bladder that occurs in association with aging.