Comparison of two experimental models of urodynamic evaluation in female rats.
OBJECTIVE
Urodynamic studies in small animals can be performed through urethral sounding or cystostomy.


OBJECTIVE
To compare the two methods of urodynamic evaluation in female rats.


METHODS
Ten female rats weighing on average 250 g, under anesthesia with urethane (1.25 mg/kg) were submitted in three repeats to an urethal catheter of 0,64 mm in external diameter for cystometric measurements of vesicle pressure(VP1) and contraction time (CT1). The catheter was extracted at a constant velocity of 0.05 cm/minute until complete exteriorization and determinations of maximal urethral pressure (UP1) and functional urethral length (FUL1). This was followed by a cystostomy with catheter PE50 and a new determination of the vesical pressure (VP2). After bladder denervation, a new cystometric record indirectly infered the maximum urethral closure pressure (UP2). The peak urethal pressure (UP3) and the functional urethral length (FUL2) were determined in another urethral sounding. The pressure registration system consisted of a continuous infusion pump regulated to a flow of 0.1 ml/minute connected both to the cystostomy catheter (PE-50) or the urethal catheter (0.64 mm) and the polygraph Narco-Biosystem. Statistical analysis employed the Wilcoxon non-parametric test


RESULTS
Mean VP1= 48.2 mmHg (11,8 SD); Mean VP2 = 38.2 mmHg (9.0 SD) "p" (VP1 X VP2) = 0.0039. Mean CT1=30.2 s (21.5 SD); Mean CT2=20.0 s(7 SD) p (CT1 X CT2) = 1.28. Mean UP1 = 47.2 mmHg (6.5 SD); Mean UP2 = 21.3 mmHg (6.6 SD), mean UP3 = 40.7 mmHg(13.3 SD) p (UP1 X UP2) = 0.002; "p" (UP1 X UP3) = 0.084; p (UP2 X UP3) = 0.002. Mean FUL1=14.2 mm (1.9 SD); Mean FUL2= 14.1 mm (1.9 SD); p (FUL1 X FUL2) = 0.64.


CONCLUSIONS
The methods employed to evaluate vesical and urethral pressures are different. The presence of the urethral catheter may be an obstructive factor. Surgical denervation up to the bladder neck level does not compromise urethral function.
Division of Urology, Department of Surgery and Anatomy, Ribeirão Preto Faculty of Medicine, University of São Paulo, SP, Brazil. anabegs@hotmail.com
Ana Beatriz Gomes de
AB
Souza
Haylton Jorge
HJ
Suaid
Carla Adelino
CA
Suaid
Silvio
S
Tucci
Adauto José
AJ
Cologna
Antonio Carlos Pereira
AC
Martins
D000818:Animals; D003559:Cystostomy / Q000592:standards*; D003714:Denervation; D004195:Disease Models, Animal; D005260:Female; D009119:Muscle Contraction / Q000502:physiology; D011312:Pressure; D051381:Rats; D017208:Rats, Wistar; D014521:Urethra / Q000503:physiopathology* / Q000601:surgery; D001743:Urinary Bladder / Q000294:innervation / Q000503:physiopathology* / Q000601:surgery; D014546:Urinary Catheterization / Q000379:methods / Q000592:standards*; D014554:Urination / Q000502:physiology*; D014563:Urodynamics / Q000502:physiology*