EXPRESSION OF TGF-BETA-1 MESSENGER-RNA AND ULTRASTRUCTURAL ALTERATIONS IN PHARMACOLOGICALLY INDUCED PROLONGED PENILE ERECTION IN A CANINE MODEL

Pupose: Transforming growth factor beta (TGF-beta) is known to induce fibrosis. Our objective was to study the role of TGF-beta as a possibl e mediator of fibrosis that may follow prolonged penile erection. Mate rials and Methods: Prolonged penile erection was induced in seven adul t male mongrel dogs by intracavernosal injection of papaverine into on e of the corpora cavernosa while the other was used as a control. Intr acavernosal pressure measurements were carried out prior to administra tion of papaverine and at the end of the procedure. Penile tissue was collected from anesthetized animals prior to euthanasia for histologic al and electron microscopic (EM) studies. RT-PCR was carried out for d etection of mRNA on same tissue samples. Results: The light microscopy showed stasis of blood in the cavernosal sinusoids. EM studies reveal ed sporadic endothelial defects, loss of plasma membrane integrity and cytoplasmic condensation. There was expression of TGF-beta 1 mRNA in 66.7% of the experimental group compared with 16.7% of the control gro up.Conclusions: Pharmacologically induced low flow prolonged penile er ection in canine models is associated with histomorphological changes in relatively short periods of time, suggesting that early therapeutic intervention is desirable. The gene expression for TGF-beta 1 may be a mediator of fibrosis; therefore the use of anti-TGF-beta agents pres ents a possible tool for therapeutic intervention.