title: Effects of Radiation on Spinal Dura Mater and Surrounding Tissue in Mice.
abstract: OBJECTIVE
  Spinal surgery in a previously irradiated field carries increased risk of perioperative complications, such as delayed wound healing or wound infection. In addition, adhesion around the dura mater is often observed clinically. Therefore, similar to radiation-induced fibrosis--a major late-stage radiation injury in other tissue--epidural fibrosis is anticipated to occur after spinal radiation. In this study, we performed histopathologic assessment of postirradiation changes in the spinal dura mater and peridural tissue in mice.
  
  
  METHODS
  The thoracolumbar transition of ddY mice was irradiated with a single dose of 10 or 20 Gy. After resection of the irradiated spine, occurrence of epidural fibrosis and expression of transforming growth factor beta 1 in the spinal dura mater were evaluated. In addition, microstructures in the spinal dura mater and peridural tissue were assessed using an electron microscope.
  
  
  RESULTS
  In the 20-Gy irradiated mice, epidural fibrosis first occurred around 12 weeks postirradiation, and was observed in all cases from 16 weeks postirradiation. In contrast, epidural fibrosis was not observed in the nonirradiated mice. Compared with the nonirradiated mice, the 10- and 20-Gy irradiated mice had significantly more overexpression of transforming growth factor beta 1 at 1 week postirradiation and in the late stages after irradiation. In microstructural assessment, the arachnoid barrier cell layer was thinned at 12 and 24 weeks postirradiation compared with that in the nonirradiated mice.
  
  
  CONCLUSIONS
  In mice, spinal epidural fibrosis develops in the late stages after high-dose irradiation, and overexpression of transforming growth factor beta 1 occurs in a manner similar to that seen in radiation-induced fibrosis in other tissue. Additionally, thinning of the arachnoid barrier cell layer was observed in the late stages after irradiation. Thus, consideration should be given to the possibility that these phenomena can occur as radiation-induced injuries of the spine.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Yokogawa
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Murakami
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Demura
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kato
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Katsuhito
authors.initials: K
authors.lastname: Yoshioka
authors.affiliation: Department of Histology and Embryology, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Histology and Embryology, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Shoichi
authors.initials: S
authors.lastname: Iseki
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, 920-8641, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuchiya
mesh_terms: D000818:Animals; D004388:Dura Mater / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D005355:Fibrosis / Q000209:etiology; D051379:Mice; D011827:Radiation; D011832:Radiation Injuries / Q000473:pathology; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
chemical_list: D053773:Transforming Growth Factor beta1