title: Penile histomorphometrical evaluation in hypertensive rats treated with sildenafil or enalapril alone or in combination: a comparison with normotensive and untreated hypertensive rats.
abstract: BACKGROUND
  Erectile dysfunction (ED) is frequently associated to hypertension and antihypertensive drugs; however, the penile morphological aspects on these situations are poorly known.
  
  
  OBJECTIVE
  Evaluate the penile morphology of untreated hypertensive rats and rats treated with enalapril or sildenafil alone or in combination to verify the hypothesis that morphological alterations promoted by hypertension on corpus cavernosum could be ameliorated by the use of angiotensin-converting enzyme inhibitors and/or phosphodiesterase type 5 inhibitors.
  
  
  METHODS
  Fifty male rats were assigned into five groups: normotensive rats, untreated spontaneously hypertensive rats (SHRs), and SHR treated with enalapril or sildenafil alone or in combination. Blood pressure was measured weekly. At the conclusion of the study, the rats were euthanized, and their penises were collected for histomorphometrical analysis.
  
  
  METHODS
  The cross-sectional areas of the penis, tunica albuginea, and corpus cavernosum were measured. The density of the corpus cavernosum structures was quantified.
  
  
  RESULTS
  Both groups of SHR rats treated with enalapril became normotensive. Untreated SHR showed no difference in penile and cavernosal cross-sectional area compared with normotensive rats; however, those rats treated with enalapril or sildenafil alone demonstrated an increase in these parameters. Rats receiving combination therapy showed no cross-sectional area differences compared with normotensive rats. Cavernosal connective tissue density was increased, while the sinusoidal spaces were diminished in untreated SHR. All treatments were effective in maintaining connective tissue density in comparison with normotensive animals. Cavernosal smooth muscle density was similar in all groups, with the exception of the combination therapy group, which demonstrated a reduction in smooth muscle.
  
  
  CONCLUSIONS
  Hypertension promoted structural alterations in the corpus cavernosum that may be related to ED. Enalapril- and sildenafil-treated animals had preservation of normal corpus cavernosum structure and an increase in penile and cavernosal cross-sectional area. The combination of these drugs showed less benefit than individual use.
authors.affiliation: Urogenital Research Unit, State University of Rio de Janeiro, Rio de Janeiro, Brazil; Institute for Humanities and Health, Federal Fluminense University, Rio das Ostras, Brazil.
authors.forename: Bruno
authors.initials: B
authors.lastname: Felix-Patrício
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Medeiros
authors.forename: Diogo B
authors.initials: DB
authors.lastname: De Souza
authors.forename: Waldemar S
authors.initials: WS
authors.lastname: Costa
authors.forename: Francisco J B
authors.initials: FJ
authors.lastname: Sampaio
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D004656:Enalapril / Q000494:pharmacology*; D007172:Erectile Dysfunction / Q000188:drug therapy; D006801:Humans; D008297:Male; D010413:Penis / Q000187:drug effects*; D010879:Piperazines / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D000068677:Sildenafil Citrate; D013449:Sulfonamides / Q000494:pharmacology*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D010879:Piperazines; D011687:Purines; D013449:Sulfonamides; D004656:Enalapril; D000068677:Sildenafil Citrate
keywords: Erectile Dysfunction; Hypertension; Morphology; Penis