Validation of a new rat model of urethral sphincter injury and leak point pressure measurements

Abdelkhalek Samy Abdelkhalek, Patrick D Clarke, Matthew A Sommers, Tyler Oe, Thomas M Andersen, Chrissie T Andersen, Eva Kildall Hejbøl, Henrik Daa Schrøder, Peter Zvara

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

AIMS: In vivo experiments were performed to establish and validate a rat model of urethral sphincter injury and to develop a method for leak point pressure (LPP) measurements performed repeatedly in the same animal.

METHODS: Twenty-four Sprague-Dawley female rats underwent bladder and epidural catheter implantation. Five days later, cystometry was performed using continuous infusion. Anesthesia with isoflurane, ketamine-xylazine (KX) or fentanyl-fluanisone-midazolam (FFM) was used. After three micturition cycles, intrathecal bupivacaine was administered leading to the suppression of reflex bladder contractions. LPP measurements were performed using vertical tilt. After the initial LPP measurement, animals underwent partial resection of the striated urethral sphincter. The effect was evaluated 6 weeks after surgery, by repeating the LPP measurement in the same animal.

RESULTS: Ten out of 19 animals showed full micturition cycles under isoflurane, and all 9 animals under KX anesthesia. No significant difference in micturition pressures (Mean ± SEM; 30.1 ± 2.3 vs. 26.8 ± 1.6 mmHg) and LPP (31.0 ± 2.4 vs. 28.0 ± 0.9 mmHg) was observed between isoflurane and KX groups, respectively. Reflex micturition was suppressed with FFM. Bupivacaine led to overflow incontinence in all cases. Sphincter injury caused fibrotic changes and a significant increase in LPP (26.4 ± 2.3 before vs. 46.9 ± 4.6 mmHg after injury, p < 0.05).

CONCLUSIONS: KX anesthesia preserves bladder contractions. Intrathecal bupivacaine eliminates reflex micturition, allowing for repeated LPP measurements in the same animal. Resection of striated sphincter resulted in increased LPP 6 weeks post injury. The site of urethral sphincter resection healed with fibrosis.

Original languageEnglish
JournalScandinavian Journal of Urology
Volume55
Issue number6
Pages (from-to)498-504
ISSN0036-5599
DOIs
Publication statusPublished - Dec 2021

Keywords

  • Urinary incontinence
  • anesthesia
  • animal model
  • leak point pressure
  • rat
  • Rats
  • Male
  • Rats, Sprague-Dawley
  • Animals
  • Urethra
  • Female
  • Urethral Diseases
  • Urination
  • Urinary Bladder

Fingerprint

Dive into the research topics of 'Validation of a new rat model of urethral sphincter injury and leak point pressure measurements'. Together they form a unique fingerprint.

Cite this