title: Evaluation of stretched electrospun silk fibroin matrices seeded with urothelial cells for urethra reconstruction.
abstract: BACKGROUND
  We investigated the feasibility of urethral reconstruction using stretched electrospun silk fibroin matrices.
  
  
  METHODS
  A novel electrospun silk fibroin matrix was prepared. The structure of the material was assessed by scanning electron microscopy and a porosity test. Canine urothelial cells were isolated, expanded, and seeded onto the material for 1 wk to obtain a tissue-engineered graft. The tissue-engineered graft was assessed using hematoxylin and eosin staining and scanning electron microscopy. A dorsal urethral mucosal defect was created in nine female beagle dogs. In the experimental group, tissue-engineered mucosa was used to repair urethra mucosa defects in six dogs. No substitute was used in the three dogs of the control group. Retrograde urethrography was performed at 1, 2, and 6 mo after grafting. The urethral grafts were analyzed grossly and histologically.
  
  
  RESULTS
  Scanning electron microscope and a porosity test revealed that the material had a three-dimensional porous structure. Urothelial cells grew on the material and showed good biocompatibility with the stretched silk fibroin matrices. Canines implanted with tissue-engineered mucosa voided without difficulty. Retrograde urethrography revealed no signs of stricture. Histologic staining showed gradual epithelial cell development and stratified epithelial layers at 1, 2, and 6 mo. The canines in the control group showed difficulty in voiding. Retrograde urethrography showed urethra stricture. Histologic staining showed that no or only one layer of epithelial cells developed. A severe inflammatory reaction was also observed in the control group.
  
  
  CONCLUSIONS
  Stretched electrospun silk fibroin matrices have good biocompatibility with urothelial cells, which could prove to be a potential material for use in urethra reconstruction.
authors.affiliation: Department of Urology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, P.R. China.
authors.forename: Minkai
authors.initials: M
authors.lastname: Xie
authors.forename: Lujie
authors.initials: L
authors.lastname: Song
authors.forename: Jihong
authors.initials: J
authors.lastname: Wang
authors.forename: Suna
authors.initials: S
authors.lastname: Fan
authors.forename: Yaopeng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yuemin
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004285:Dogs; D005260:Female; D005349:Fibroins / Q000627:therapeutic use* / Q000648:ultrastructure; D015994:Incidence; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods*; D016378:Tissue Transplantation / Q000379:methods*; D016896:Treatment Outcome; D014521:Urethra / Q000601:surgery*; D014555:Urination Disorders / Q000453:epidemiology; D019459:Urothelium / Q000166:cytology* / Q000648:ultrastructure
chemical_list: D005349:Fibroins
keywords: Biomaterial; Silk fibroin; Tissue engineering; Urethra reconstruction