title: Sustained local application of epidermal growth factor to accelerate reepithelialization of tracheal grafts.
abstract: OBJECTIVE
  Epidermal growth factor-loaded gelatin microspheres were tested for potential to accelerate tracheal allograft reepithelialization.
  
  
  METHODS
  Epidermal growth factor-loaded gelatin microspheres were prepared by optimal double-phase emulsified condensation polymerization. One hundred age-matched allogeneic mice were randomly allocated to local administration of 1 mg epidermal growth factor-loaded gelatin microspheres (containing 1 microg epidermal growth factor), 1 mg gelatin microspheres, 1 microg epidermal growth factor, or nothing (control, all groups n = 25) during orthotopic transplant of C57BL/6 donor tracheal segments into BALB/c recipients without immunosuppressors. On days 7, 14, 21, 35, and 52 after transplant, 5 mice per group were killed and evaluated by histologic assessment and scanning electronic microscopy for reepithelialization and fibrosis of tracheal grafts.
  
  
  RESULTS
  Mean diameter of gelatin microspheres was 107 microm. Microspheres could not be fully degraded until 35 days after transplant in vivo. On days 7, 14, and 21, epithelium score and ratio of lamina propria to tracheal cartilage were not statistically different between mice with epidermal growth factor-loaded gelatin microspheres and other groups. On days 35 and 52, however, epithelium score was higher and ratio of lamina propria to tracheal cartilage was lower in epidermal growth factor-loaded gelatin microsphere recipients; these mice also had almost complete differentiation of regenerated epithelium into ciliated columnar epithelium on days 35 and 52, earlier than in other groups.
  
  
  CONCLUSIONS
  Gelatin microspheres act as a functional vector for epidermal growth factor. Sustained local application of epidermal growth factor could accelerate reepithelialization of tracheal allografts.
authors.affiliation: Department of Thoracic Surgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
authors.forename: Jinbo
authors.initials: J
authors.lastname: Zhao
authors.forename: Yong
authors.initials: Y
authors.lastname: Han
authors.forename: Zhibo
authors.initials: Z
authors.lastname: Liang
authors.forename: Zhipei
authors.initials: Z
authors.lastname: Zhang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Lu
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Yan
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D002923:Cilia / Q000187:drug effects; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004815:Epidermal Growth Factor / Q000008:administration & dosage*; D004847:Epithelial Cells / Q000187:drug effects* / Q000473:pathology / Q000637:transplantation*; D005355:Fibrosis; D005780:Gelatin / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D012038:Regeneration; D020545:Respiratory Mucosa / Q000187:drug effects* / Q000473:pathology / Q000637:transplantation*; D013499:Surface Properties; D013997:Time Factors; D014132:Trachea / Q000187:drug effects* / Q000473:pathology / Q000637:transplantation*; D014184:Transplantation, Homologous
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004815:Epidermal Growth Factor; D005780:Gelatin