Urethral monopolar cauterization: alternative infravesical obstruction model in male rats

We aimed to determine which method gives the most consistent results between urethral monopolar cauterization and standard urethral partial ligation methods for the urethral obstruction model.

Thirty male rats were randomly divided into control, partial ligation, and monopolar cauterization groups. Six weeks after experimental procedures, the experimental groups were evaluated cystometrically, biochemically, and histologically.

According to the cystometric results, bladder capacity, baseline bladder pressure, and compliance data of the monopolar cauterization group were higher than those of the partial ligation and monopolar cauterization groups (p<0.05 and p<0.01, respectively). As a biochemical evaluation, malondialdehyde levels in bladder tissues of group control were higher than partial ligation and monopolar cauterization groups (p<0.05 and p<0.01, respectively). The collagen type I level of the control group was higher than the partial ligation and monopolar cauterization groups (p<0.01 and p<0.05, respectively). Collagen type III levels of the monopolar cauterization group were higher than those of the control group (p<0.01), but the Collagen type I/Collagen type III and transforming growth factor-β levels of the monopolar cauterization group were significantly lower than those of the control group (p<0.001). As a histological evaluation (hematoxylin and eosin), fibrosis in the lamina propria was more prominent in the monopolar cauterization group than in the control group (p<0.05). In addition, the muscular thickness was higher in the monopolar cauterization group compared with control and partial ligation groups (p<0.001 and p<0.01, respectively).

The needle-tipped monopolar cauterization of the posterior urethra may be the method of choice for creating a chronic infravesical obstruction model of infravesical obstruction in male rats.