Complete Penile Disassembly for Repair of Epispadias Causes Erectile Tissue Alteration Through Transforming Growth Factor Beta 1 Overexpression in a Rabbit Model

Abstract

To investigate corporal tissue viability and changes in endothelial content following current techniques used for epispadias repair in an animal model. Sixty rabbits were allocated into 3 groups: sham operation (penile degloving), complete disassembly model, and Cantwell-Ransley model. On weeks 2, 4, 12, and 24 postoperation, the penile tissue was harvested and processed for (1) Masson's trichrome staining for smooth muscle cell (SMC)-to-collagen ratios, (2) immunohistochemical staining for endothelial factor (CD31), and transforming growth factor beta 1 (TGF-β1) (3) terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick-end labeling (TUNEL) assay to detect apoptosis. Masson trichrome staining of corporal tissue showed significant decrease in SMC-to-collagen ratio in complete disassembly group compared with sham operation group. The expression of CD31 was significantly lower (P <.05) in complete disassembly group compared with the other groups at all time points, whereas no significant difference was observed between the Cantwell-Ransley group and the sham operation group. Moreover, apoptotic index was markedly higher in the complete disassembly group compared with the 2 other operation groups (P <.05). Immunohistochemistry also showed a significantly higher expression of TGF-β1 in the penile tissue after complete disassembly than Cantwell-Ransley or sham operation. Complete detachment of the urethra from the corpus cavernosa may result in endothelial dysfunction, alteration of SMC content of erectile tissue, and replacement of the native cavernosal tissue with fibrotic tissue. An increased expression of TGF-β1, following the complete disassembly technique, might be one of the important factors causing the abovementioned alterations.