Biochemical analysis of urethral collagen content after tubularized incised plate urethroplasty: an experimental study in rabbits

The aim of the present study was the biochemical analysis of tissue hydroxyproline levels in incised urethral plates in order to show the total collagen content after the Snodgrass operation in the hypospadiac rabbit model. The study comprised 21 male New Zealand rabbits, (2.2–2.4 kg). The animals were randomly allocated to three groups each containing seven rabbits as follows: group 1, the ventral urethra was completely excised and a model of hypospadias formed. A full-thickness incision was made on the distal dorsal urethra, a feeding tube was placed as an urethral catheter and both urethral wings were sutured ventrally. Group 2, inserting an iris knife into the urethra, the ventral wall was incised mimicking an urethrotome. Group 3 consisted of normal control rabbits to determine the basal tissue hydroxyproline level. A slight increase in the hydroxyproline level was observed in the ventral part of the urethral tissue compared to the dorsal part in both groups 1 and 2; however, these differences were not significant. After the Snodgrass operation in the rabbit model, no significant differences were observed in the hydroxyproline levels of the dorsal and ventral parts of the urethra or between these and of the controls. Further studies are required in order to determine the mechanism underlying urethral healing through normal re-epithelization without excess collagen deposition after incised urethral plate urethroplasty.