title: Effects of cavernous nerve reconstruction on expression of nitric oxide synthase isoforms in rats.
abstract: OBJECTIVE
  To evaluate the expression of nitric oxide synthase (NOS) isoforms after various reconstruction techniques in rats, to improve the understanding of neuronal repair mechanisms after radical prostatectomy, as Schwann cell-seeded guidance tubes have been shown to promote cavernous nerve regeneration, and glial cell-line-derived neurotrophic factor (GDNF)-overexpressing Schwann cells enhance nerve regenerative capacity.
  
  
  METHODS
  Segments (5 mm) of the cavernous nerve were excised bilaterally, followed by immediate bilateral microsurgical reconstruction. In four rats per group, the eight nerves were reconstructed by autologous nerve grafting (A), interposition of Schwann cell-seeded silicon tubes (B), or silicon tubes seeded with GDNF-hypersecreting Schwann cells (C). Further rats were either sham-operated (D) or had nerve excision without repair (E). Erectile function was evaluated after 6 weeks by re-laparotomy, electrical nerve stimulation and morphological evaluation of reconstructed nerves. NOS isoform mRNA expression was analysed by reverse transcription-polymerase chain reaction in tissue specimens taken from the corpora cavernosa.
  
  
  RESULTS
  GDNF-transduced Schwann cell grafts restored erectile function better than untransduced Schwann cell and autologous nerve grafts (88% vs 75% vs 38%; not significant). Tissue specimens in group C had the highest expression of neuronal NOS mRNA in relation to the neuronal marker PGP9.5 among all treatment groups (not significant). Compared to nerve grafts (A) and negative controls (E) nNOS/PGP9.5 expression was significantly higher (P < 0.05). Both inducible NOS and endothelial NOS expression did not differ significantly among the various groups. Morphological evaluation showed significantly larger cross-sectional areas and a higher percentage of neural tissue than in untransduced Schwann cell grafts (P < 0.05).
  
  
  CONCLUSIONS
  Restoration of erectile function is paralleled by an increase of neuronal NOS expression in rats. Further experiments will determine the physiological role of neuronal NOS in erectile nerve repair processes.
authors.affiliation: Department of Urology, Ludwig-Maximilians-University, Munchen, Germany. Boris.Schlenker@med.unimuenchen.de
authors.forename: Boris
authors.initials: B
authors.lastname: Schlenker
authors.forename: Kaspar
authors.initials: K
authors.lastname: Matiasek
authors.forename: Dieter
authors.initials: D
authors.lastname: Saur
authors.forename: Christian
authors.initials: C
authors.lastname: Gratzke
authors.forename: Ricarda M
authors.initials: RM
authors.lastname: Bauer
authors.forename: Yared
authors.initials: Y
authors.lastname: Herouy
authors.forename: Christian
authors.initials: C
authors.lastname: Arndt
authors.forename: Armin
authors.initials: A
authors.lastname: Blesch
authors.forename: Rudolf
authors.initials: R
authors.lastname: Hartung
authors.forename: Christian G
authors.initials: CG
authors.lastname: Stief
authors.forename: Norbert
authors.initials: N
authors.lastname: Weidner
authors.forename: Florian
authors.initials: F
authors.lastname: May
mesh_terms: D000818:Animals; D017690:Cell Transplantation / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000378:metabolism; D018783:Impotence, Vasculogenic / Q000601:surgery*; D008297:Male; D009416:Nerve Regeneration / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010410:Penile Erection / Q000502:physiology; D010413:Penis / Q000201:enzymology / Q000294:innervation* / Q000601:surgery; D051381:Rats; D011916:Rats, Inbred F344; D020127:Recovery of Function; D012583:Schwann Cells / Q000378:metabolism / Q000637:transplantation*
chemical_list: D051100:Glial Cell Line-Derived Neurotrophic Factor; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III