title: Cavernous smooth muscle hyperplasia in a rat model of hyperlipidaemia-associated erectile dysfunction.
abstract: What's known on the subject? and what does the study add? Increased cavernous smooth muscle content has been repeatedly observed in rat models of hyperlipidaemia - associated erectile dysfunction. This study shows that the increased smooth muscle content is due to hyperplasia.
  
  
  OBJECTIVE
  • To investigate the structural changes, including possible smooth muscle hyperplasia, in the penis of a hyperlipidaemia-associated erectile dysfunction (ED) animal model.
  
  
  METHODS
  • Hyperlipidaemia was induced in rats through a high-fat diet. • Penile tissues of normal and hyperlipidaemic rats were stained with Alexa-488-conjugated phalloidin and/or with antibodies against rat endothelial cell antigen, neuronal nitric oxide synthase (nNOS), and collagen type IV (Col-IV) before image and statistical analyses were carried out. • The main outcome measures were the smooth muscle, endothelial, Col-IV and nNOS content of the corpus cavernosum.
  
  
  RESULTS
  • Phalloidin intensely stained all smooth muscle in the penis, revealing the circular and longitudinal components of cavernous smooth muscle (CSM). • The CSM content was significantly higher in the hyperlipidaemic than in the normal rats (P < 0.05). • Cell numbers in both circular and longitudinal CSM were significantly higher in the hyperlipidaemic than in the normal rats (P < 0.05). • Cavernous endothelial content was significantly lower in hyperlipidaemic than in normal rats (P < 0.05). • nNOS-positive nerves within the dorsal nerves, around the dorsal arteries, and in the corpora cavernosa were all significantly lower in the hyperlipidaemic than in the normal rats (P < 0.05).
  
  
  CONCLUSIONS
  • Hyperlipidaemia is associated with reduced nNOS-positive nerves, reduced endothelium, and increased CSM in the penis. • The increased CSM is attributable to hyperplasia. • These structural changes may explain why hyperlipidaemic men are more likely to develop ED.
authors: Knuppe Molecular Urology Laboratory, Department of Urology, University of California, San Francisco, USA.
authors: Xuefeng
authors: X
authors: Qiu
authors: Thomas M
authors: TM
authors: Fandel
authors: Guiting
authors: G
authors: Lin
authors: Yun-Ching
authors: YC
authors: Huang
authors: Yu-Tian
authors: YT
authors: Dai
authors: Tom F
authors: TF
authors: Lue
authors: Ching-Shwun
authors: CS
authors: Lin
mesh_terms: D000818:Animals; D024141:Collagen Type IV / Q000378:metabolism; D006949:Hyperlipidemias / Q000150:complications / Q000473:pathology*; D006965:Hyperplasia / Q000473:pathology; D018783:Impotence, Vasculogenic / Q000209:etiology / Q000473:pathology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000473:pathology*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D010413:Penis / Q000098:blood supply / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D024141:Collagen Type IV; D052248:Nitric Oxide Synthase Type I