title: Chitosan tubes can restore the function of resected phrenic nerves.
abstract: OBJECTIVE
  We previously reported that the phrenic nerve could be morphologically repaired by implantation of a chitosan nanofibre tube (C-tube). In the current study, we investigated whether implantation of C-tubes could improve the function of an injured phrenic nerve using a beagle dog model.
  
  
  METHODS
  Seven beagle dogs underwent right thoracotomy under general anaesthesia. An approximately 5 mm length of the right phrenic nerve was resected. Five dogs had a C-tube implantation (C-tube group) and other two dogs did not have the C-tube implantation (control group). Diaphragm movements were longitudinally measured by X-ray fluoroscopy before surgery, immediately after the surgery, and 3, 6 and 12 months after the surgery. The diaphragm movement was determined by diaphragm levels at inspiration and expiration phases, and the excursion difference between them was calculated. At 12 months after the surgery, rethoracotomy was performed to examine electrical phrenic nerve conduction. The C-tube and phrenic nerve were then excised for histological assessment of nerve regeneration.
  
  
  RESULTS
  Three of the five animals of the C-tube group showed improvement of diaphragm movement with time. In these three animals, slow phrenic nerve conduction was observed. Histological assessment showed that the injured nerve was connected by newly regenerating nerve fibres surrounded by granulation tissue within the C-tube. On the other hand, the animals in the control group and two animals of the C-tube group showed neither improved diaphragm movement, nor electrical conduction to the diaphragm. No nerve fibre regeneration was found by histology.
  
  
  CONCLUSIONS
  Our results suggest that, in addition to morphological improvement, C-tube implantation can functionally improve the injured phrenic nerve by promoting phrenic nerve regeneration.
authors: Department of General and Cardiothoracic Surgery, Kanazawa University, Kanazawa, Japan tanapiro@ipch.jp.
authors: Nobuyoshi
authors: N
authors: Tanaka
authors: Department of General and Cardiothoracic Surgery, Kanazawa University, Kanazawa, Japan.
authors: Isao
authors: I
authors: Matsumoto
authors: Department of General and Cardiothoracic Surgery, Kanazawa University, Kanazawa, Japan.
authors: Mitsutaka
authors: M
authors: Suzuki
authors: Department of General and Cardiothoracic Surgery, Kanazawa University, Kanazawa, Japan.
authors: Mami
authors: M
authors: Kaneko
authors: Department of General and Cardiothoracic Surgery, Kanazawa University, Kanazawa, Japan.
authors: Kanae
authors: K
authors: Nitta
authors: Department of General and Cardiothoracic Surgery, Kanazawa University, Kanazawa, Japan.
authors: Ryuta
authors: R
authors: Seguchi
authors: Department of Molecular and Cellular Pathology, Kanazawa University, Kanazawa, Japan.
authors: Akishi
authors: A
authors: Ooi
authors: Department of General and Cardiothoracic Surgery, Kanazawa University, Kanazawa, Japan.
authors: Hirofumi
authors: H
authors: Takemura
mesh_terms: D000818:Animals; D048271:Chitosan / Q000737:chemistry*; D003964:Diaphragm / Q000000981:diagnostic imaging / Q000294:innervation*; D004285:Dogs; D004867:Equipment Design; D045853:Exhalation; D020007:Implants, Experimental; D001239:Inhalation; D023421:Models, Animal; D057139:Nanofibers; D009416:Nerve Regeneration; D009431:Neural Conduction; D010791:Phrenic Nerve / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D011859:Radiography; D020127:Recovery of Function; D013997:Time Factors; D054457:Tissue Scaffolds
chemical_list: D048271:Chitosan
keywords: Chitosan tube; Nerve regeneration; Phrenic nerve