Three new experimental models of anterior urethral stricture in rabbits

Abstract

Background: This study describes and compares three surgical procedures for the construction of urethral stricture (US) models in rabbits.Methods: Forty adult male rabbits were allocated to four groups: 36 rabbits were randomly assigned to three experimental groups, while the remaining 4 were assigned to a sham group. The penis was separated from the rectum. Then along the ventral midline, a longitudinal penile skin incision was made while ensuring that the urethral mucosa was intact and the muscular layer was not completely incised. In group 1 (n=12), ventral semi-circumferential mucosa electrocoagulation of a 1-cm length of the anterior urethra was performed until ulceration occurred. In group 2 (n=12), the ventral urethral mucosa was incised, and electrocoagulation of the dorsal semi-circumferential mucosa was performed. In group 3 (n=12), wholecircumferential mucosa electrocoagulation was performed. In group 4 (n=4), no special treatment was performed. Four weeks later, urethrography, urethroscopy, and histological evaluation were carried out. Results:The weights of the rabbits in the four groups were comparable. There was no significant difference between groups 2 and 3 with regard to operative time, but the operative time in these groups was significantly longer than that in group 1 (group 2 vs. group 1: P<0.05, group 3 vs. group 1: P<0.001).After the surgery, urinary fistula with infection occurred in one rabbit in group 1, and one rabbit died due to urethral atresia in group 3. According to the urethrography and urethroscopy findings, 9 out of 12 rabbits in group 1, 5 out of 12 rabbits in group 2, and 11 out of 11 rabbits in group 3 developed US, while no rabbits in the sham group developed US. Histopathological examination revealed injury to the urothelium, inflammatory infiltration, a decrease in the amount of blood vessels and smooth muscle fibers, and a decrease in the amount of collagen fibers.Conclusions: Compared with the semi-circumferential procedures, the whole-circumferential procedure had a higher success rate. Therefore, this procedure seems to have potential for the construction of longsegment rabbit US models.

In search of the ideal animal model for urethral strictures for therapeutic purposes

“…The recent study of Yao et al describes and compares three different surgical procedures for establishing US animal models in New Zealand rabbits opposing them to a control group (9). All used the principles of open surgery with urethra dissection and suturing after the intervention; however, the stricture formation was based on the electrocoagulation effect.…”

“…As expected, the highest SR was observed in the circumferential electrocoagulation group, but at the cost of a higher risk for the occurrence of urethral obliteration resulting in the death of some animals. As an alternative, ventral semi-circumferential electrocoagulation has been proposed as an effective and safe US model (9).…”

Material Characteristic of an Innovative Stent for the Treatment of Urethral Stenosis

“…The clinical symptoms of urethral stricture include urinary problems such as increased micturition with less urine output, lower urinary tract infections, discomfort and decreased quality of life, sepsis, bladder stone formation, kidney failure and, in the most serious cases, death. Urethral stricture occurs as a result of tissues fibrosis, which leads to a reduction in the urethral lumen that impedes the free flow of urine and other metabolic products [4][5][6][7][8]. All kinds of injuries to the epithelial and spongy parts are considered to be the cause of this pathology, which subsequently leads to changes in the cellular matrix of the urethral tissues.…”