title: Peripheral nerve repair: monitoring by using gadofluorine M-enhanced MR imaging with chitosan nerve conduits with cultured mesenchymal stem cells in rat model of neurotmesis.
abstract: OBJECTIVE
  To observe the longitudinal changes of nerve repair in rats after tissue-engineered construct implantation at magnetic resonance (MR) imaging and to determine whether the enhanced nerve regeneration with use of tissue-engineered constructs could be monitored with gadofluorine M-enhanced MR imaging or nerve T2 relaxation time measurement.
  
  
  METHODS
  All experimental protocols were approved by the institutional Animal Use and Care Committee. Tissue-engineered constructs were prepared by seeding mesenchymal stem cells (MSCs) into chitosan nerve tubes. Thirty-six rats with sciatic nerve transection injury underwent nerve tube implantation with (n = 18) or without (n = 18) MSC seeding. Sequential T2 measurement, gadofluorine M-enhanced MR imaging, and sciatic function index measurement were performed over an 8-week follow-up period, with histologic assessments performed at regular intervals. T2 relaxation times and signal intensity at gadofluorine M-enhanced T1-weighted imaging were measured and were compared by using repeated-measures analysis of variance followed by the Student-Neuman-Keuls post-hoc test for multiple pairwise comparisons.
  
  
  RESULTS
  Nerve T2 relaxation times and gadofluorine M enhancement, as well as functional changes, showed a similar time course. Nerves implanted with MSC-seeded tubes achieved slightly better functional recovery and enhanced nerve regeneration while showing a slower return to baseline T2 relaxation time and a more rapid decline in gadofluorine M enhancement compared with nerves implanted with chitosan tubes alone. T2 values of the distal portion of transected nerves showed a more rapid return to baseline level than did gadofluorine M enhancement.
  
  
  CONCLUSIONS
  Peripheral nerve repair with use of tissue-engineered constructs can be monitored by using gadofluorine M-enhanced MR imaging and T2 relaxation time measurements. T2 relaxation time seems more sensitive than gadofluorine M-enhanced MR imaging for detecting nerve regeneration.
authors: Department of Radiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yanjiang Road West, Guangzhou, Guangdong, China.
authors: Cheng-De
authors: CD
authors: Liao
authors: Fang
authors: F
authors: Zhang
authors: Ruo-Mi
authors: RM
authors: Guo
authors: Xiao-Mei
authors: XM
authors: Zhong
authors: Jun
authors: J
authors: Zhu
authors: Xue-Hua
authors: XH
authors: Wen
authors: Jun
authors: J
authors: Shen
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001672:Biocompatible Materials; D002478:Cells, Cultured; D048271:Chitosan; D003287:Contrast Media; D048091:Guided Tissue Regeneration; D008279:Magnetic Resonance Imaging / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D009416:Nerve Regeneration / Q000502:physiology*; D009942:Organometallic Compounds; D059348:Peripheral Nerve Injuries / Q000628:therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D023822:Tissue Engineering; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D003287:Contrast Media; D009942:Organometallic Compounds; C477144:gadofluorine; D048271:Chitosan