Short-term effects of suprapubic catheterization on detrusor muscle contraction in a rat model of postoperative urinary dysfunction

Abstract

Catheterization is commonly performed in pelvic surgery to manage postoperative urinary dysfunction. However, little is known about the effects of catheterization on bladder function, although catheterization can drain urine from the bladder. In the present study, we evaluated the short-term effects of catheterization on detrusor muscle contraction in a rat model of postoperative urinary dysfunction due to bilateral accessory nerve injury (BACNI). Ten-week-old male Wistar/ST rats were divided into sham, sham+catheterization (sham+C), BACNI, and BACNI+catherterization (BACNI+C) groups. The sham+C and BACNI+C groups underwent catheter placement in the bladder dome prior to sham or BACNI surgery and intermittent bladder drainage during the observation period. Four hours after surgery, the bladders were excised and subjected to isometric tension study and immunofluorescence staining. Bladder overdistension and overflow urinary incontinence were observed in the BACNI group, not the BACNI+C group. The contractile responses of the detrusor muscle to 80 mM KCl, carbachol, and electrical field stimulation (EFS) were enhanced in the BACNI group compared to the sham group; the enhanced contractile responses to EFS were improved in the BACNI+C group. The ratio of the detrusor muscle layer area to the total bladder area increased with increasing interstitial area ratio in the BACNI and BACNI+C groups, while the total bladder area increased in the sham+C and BACNI+C groups. These results suggest that catheterization does not improve the augmentation of detrusor muscle contraction and increase in the detrusor muscle layer area ratio immediately after BACNI and that catheterization causes bladder hypertrophy.