title: The distribution of neuronal and inducible nitric oxide synthase in urethral stricture formation.
abstract: OBJECTIVE
  The distribution of neuronal (n) and inducible (i) nitric oxide synthase (NOS) may have a role in the maintenance of normal urethral spongiosum and during the development of spongiofibrosis in urethral stricture disease.
  
  
  METHODS
  Eight normal and 33 strictured human bulbar urethras were studied by histological and immunohistochemical techniques for the neuronal markers S-100, nNOS and iNOS. The smooth muscle-to-collagen ratio was calculated by morphometric analysis of Masson's trichrome sections. Immunohistochemical staining patterns of the neuronal markers in normal urethral tissue was compared to that in urethral stricture tissue with spongiofibrosis.
  
  
  RESULTS
  The smooth muscle-to-collagen ratio was significantly lower in the strictured urethra compared to that in the control group (p = 0.001). In the strictured bulbar urethra nNOS immunoreactivity was decreased compared to that in normal urethral tissue. The severity of spongiofibrosis corresponded to the loss of nNOS immunoreactivity. iNOS immunoreactivity was found in strictured urethral epithelium and spongiosal tissue, whereas the control group was nonimmunoreactive to iNOS.
  
  
  CONCLUSIONS
  Urethral stricture formation is a fibrotic process associated with significant changes in NOS metabolism. Abnormal collagen synthesis following urethral trauma may be stimulated by inappropriate iNOS activity. A functional nerve supply to the urethral spongiosum seems to be crucial in the maintenance of the unique ultrastructure of the urethral spongiosum.
authors.affiliation: Department of Urology and Pediatrics, University of California-San Francisco Children's Medical Center, University of California-San Francisco, 94143, USA.
authors.forename: Andre G
authors.initials: AG
authors.lastname: Cavalcanti
authors.forename: Selcuk
authors.initials: S
authors.lastname: Yucel
authors.forename: Donna Y
authors.initials: DY
authors.lastname: Deng
authors.forename: Jack W
authors.initials: JW
authors.lastname: McAninch
authors.forename: Laurence S
authors.initials: LS
authors.lastname: Baskin
mesh_terms: D000328:Adult; D000368:Aged; D005355:Fibrosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000502:physiology*; D052248:Nitric Oxide Synthase Type I; D009418:S100 Proteins / Q000032:analysis; D014525:Urethral Stricture / Q000201:enzymology* / Q000209:etiology* / Q000473:pathology
chemical_list: D009418:S100 Proteins; C496320:NOS1 protein, human; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I