title: Incorporation of chitosan microspheres into collagen-chitosan scaffolds for the controlled release of nerve growth factor.
abstract: BACKGROUND
  Artifical nerve scaffold can be used as a promising alternative to autologous nerve grafts to enhance the repair of peripheral nerve defects. However, current nerve scaffolds lack efficient microstructure and neurotrophic support.
  
  
  METHODS
  Microsphere-Scaffold composite was developed by incorporating chitosan microspheres loaded with nerve growth factor (NGF-CMSs) into collagen-chitosan scaffolds (CCH) with longitudinally oriented microchannels (NGF-CMSs/CCH). The morphological characterizations, in vitro release kinetics study, neurite outgrowth assay, and bioactivity assay were evaluated. After that, a 15-mm-long sciatic nerve gap in rats was bridged by the NGF-CMSs/CCH, CCH physically absorbed NGF (NGF/CCH), CCH or nerve autograft. 16 weeks after implantation, electrophysiology, fluoro-gold retrograde tracing, and nerve morphometry were performed.
  
  
  RESULTS
  The NGF-CMSs were evenly distributed throughout the longitudinally oriented microchannels of the scaffold. The NGF-CMSs/CCH was capable of sustained release of bioactive NGF within 28 days as compared with others in vitro. In vivo animal study demonstrated that the outcomes of NGF-CMSs/CCH were better than those of NGF/CCH or CCH.
  
  
  CONCLUSIONS
  Our findings suggest that incorporation of NGF-CMSs into the CCH may be a promising tool in the repair of peripheral nerve defects.
authors.affiliation: Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China; Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Zeng
authors.affiliation: Department of Clinical Immunology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
authors.forename: Mengyao
authors.initials: M
authors.lastname: Rong
authors.affiliation: Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
authors.forename: Xueyu
authors.initials: X
authors.lastname: Hu
authors.affiliation: Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.affiliation: Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
authors.forename: Fengyu
authors.initials: F
authors.lastname: Qi
authors.affiliation: Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
authors.forename: Jinghui
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
authors.forename: Zhuojing
authors.initials: Z
authors.lastname: Luo
mesh_terms: D000818:Animals; D048271:Chitosan; D003094:Collagen; D003692:Delayed-Action Preparations / Q000627:therapeutic use; D065546:Drug Liberation; D008297:Male; D008863:Microspheres; D020932:Nerve Growth Factor / Q000008:administration & dosage*; D051381:Rats; D012584:Sciatic Nerve / Q000187:drug effects / Q000293:injuries*
chemical_list: D003692:Delayed-Action Preparations; D003094:Collagen; D048271:Chitosan; D020932:Nerve Growth Factor