RESUMO
AIMS: The objective of this study was to evaluate the similarities and differences of the urethral morphological and functional changes following external urethral sphincter EUS injury in male and female rats. METHODS: 30 female and 30 male age-matched Wistar rats were used in the experiments. Half of them underwent electrocauterization of the surrounding tissues lateral to the urethra at the level of the (EUS) and the others, a sham operation. At 2, 6, and 16 weeks after surgeries they underwent anesthetized cystometry, measurement of leak point pressure (LPP) and their urethras were harvested for morphological analyses. RESULTS: There were no differences in cystometric parameters between sex-time-matched animals, ensuring normal bladder function in the manipulated animals. The mean LPP in male and female rats was lower compared with sham animals. Age-time-matched sham operated male rats exhibited a higher LPP compared with female rats. The reduction in LPP comparing electrocauterized and sham time-matched animals was more pronounced in male rats than in female rats. Electrocauterization produced urethral collagen deposition and nerve damage in both male and female animals. Muscle atrophy and disruption also occurred, being more evident in female rats. CONCLUSIONS: The urethras of male and female rats exhibited a similar morphological and functional response to electrocauterization. The time-course evaluation revealed that the male animal model is as reliable, reproducible and long-lasting as the female model. Intact males had a higher LPP than female rats and the nerve injury led to a more drastic impairment of this mechanism.