title: Histological and ultrastructural alterations in an animal model of Peyronie's disease.
abstract: OBJECTIVE
  To determine the role of transforming growth factor beta (TGF-beta), one of the cytokines known to induce tissue fibrosis, in the induction of a Peyronie's-like condition, and to produce an animal model for the further study of Peyronie's disease.
  
  
  METHODS
  Twenty-four adult male Sprague-Dawley rats were divided into two groups: in group 1, different concentrations of cytomodulin, a synthetic heptapeptide with TGF-beta-like activity, were injected into the tunica of each of 18 rats and six rats group 2 received saline injections as a control. The tunical tissues were taken after 3 days, 2 and 6 weeks and were examined histologically using Hart and trichrome stains. Electron microscopy was used to examine the ultrastructural changes in the same tissue samples.
  
  
  RESULTS
  There were histological and ultrastructural alterations in 15 of 18 rats in group 1 (cytomodulin-injected), especially in tissue examined after 6 weeks. The most prominent histological changes were chronic inflammatory cellular infiltration, focal and diffuse elastosis, thickening, disorganization and clumping of the collagen bundles. The ultrastructural changes were in the form of densely packed collagen, fragmented and scarce elastic fibres, separation of neuronal fibres by interposing clumps of packed collagen, and perivascular collagen deposition as a part of the reorganization of the interstitial matrix.
  
  
  CONCLUSIONS
  Cytomodulin can induce a Peyronie's-like condition in the rat penis, which may explain the role of TGF-beta in the pathogenesis of Peyronie's disease. With further refinement, such rats may be used as an experimental model for studies of Peyronie's disease.
authors.affiliation: Department of Urology, University of California School of Medicine, San Francisco 94143-0738, USA.
authors.forename: A I
authors.initials: AI
authors.lastname: El-Sakka
authors.forename: M U
authors.initials: MU
authors.lastname: Hassan
authors.forename: L
authors.initials: L
authors.lastname: Nunes
authors.forename: R S
authors.initials: RS
authors.lastname: Bhatnagar
authors.forename: T S
authors.initials: TS
authors.lastname: Yen
authors.forename: T F
authors.initials: TF
authors.lastname: Lue
mesh_terms: D000818:Animals; D003094:Collagen / Q000032:analysis; D004195:Disease Models, Animal; D008297:Male; D008854:Microscopy, Electron; D010411:Penile Induration / Q000139:chemically induced / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
chemical_list: D016212:Transforming Growth Factor beta; D003094:Collagen