title: Comparative study between porcine small intestinal submucosa and buccal mucosa in a partial urethra substitution in rabbits.
abstract: OBJECTIVE
  Several urethral conditions may require tissue substitution. One collagen-base biomaterial that recently emerged as an option is small intestinal submucosa (SIS). The aim of this study was to compare the results of SIS and buccal mucosa for urethral substitution in rabbits.
  
  
  METHODS
  Thirty-six North Folk male rabbits were randomized into three groups. In all animals, a 10 × 5 mm urethral segment was excised, and the urethral defect was repaired using a one-layer SIS patch (group I [GI]); four-layer SIS (group II [GII]); or buccal mucosa (group III [GIII]). Urethrography was performed preoperatively and after 12 weeks. After sacrifice, graft retraction was objectively measured using Scion Image(®) computer analysis and by calculation of ellipse area. The grade of fibrosis, inflammatory reaction, vascular/epithelial regeneration, and collagen III/I ratio were analyzed by hematoxylin/eosin and Picrosirius red staining.
  
  
  RESULTS
  Urethrography confirmed a wide urethral caliber without any signs of strictures after surgery. Urethral fistulae was diagnosed in 8.3% of cases (1 animal each group). Average graft shrinkage was 55.2% in GI; 44.2% in GII; and 57.2% in GIII (p<0.05). The intensity of chronic inflammation, fibrosis, epithelium regeneration, and neovascularization was similar in all groups (p>0.05). Collagen III/I ratio was higher in GII (GI: 119.6; GII: 257.2 and GIII: 115.0); p<0.01.
  
  
  CONCLUSIONS
  The four-layer SIS is more advantageous than the one-layer SIS and buccal mucosa for urethral substitution in rabbits.
authors.affiliation: Department of Urology, São Paulo State University-UNESP, Botucatu, Brazil. kawano@fmb.unesp.br
authors.forename: Paulo Roberto
authors.initials: PR
authors.lastname: Kawano
authors.forename: Oscar Eduardo Hidetoshi
authors.initials: OE
authors.lastname: Fugita
authors.forename: Hamilto Akihissa
authors.initials: HA
authors.lastname: Yamamoto
authors.forename: Juliany Gomes
authors.initials: JG
authors.lastname: Quitzan
authors.forename: Carlos
authors.initials: C
authors.lastname: Padovani
authors.forename: João Luiz
authors.initials: JL
authors.lastname: Amaro
mesh_terms: D000818:Animals; D003094:Collagen / Q000378:metabolism; D007413:Intestinal Mucosa / Q000637:transplantation*; D007421:Intestine, Small / Q000637:transplantation*; D008297:Male; D009061:Mouth Mucosa / Q000637:transplantation*; D011817:Rabbits; D013194:Staining and Labeling; D034421:Sus scrofa; D014521:Urethra / Q000601:surgery*
chemical_list: D003094:Collagen