title: Radioprotective effect of lidocaine on function and ultrastructure of salivary glands receiving fractionated radiation.
abstract: OBJECTIVE
  Radiation-induced xerostomia still represents a common side effect after radiotherapy for head-and-neck malignancies. The aim of the present study was to examine the radioprotective effect of lidocaine hydrochloride during fractionated radiation in an experimental animal model.
  
  
  METHODS
  To evaluate the influence of different radiation doses on salivary gland function and the radioprotective effect of lidocaine, rabbits were irradiated with 15, 25, 30, and 35 Gy (equivalent doses in 2-Gy fractions equivalent to 24, 40, 48, and 56 Gy, respectively). Lidocaine hydrochloride (10 and 12 mg/kg) was administered before every radiation fraction in the treatment groups. Salivary gland function was assessed by flow sialometry and sialoscintigraphy, and the morphologic changes were evaluated using transmission electron microscopy.
  
  
  RESULTS
  Functional impairment was first observed after 35 Gy and pretreatment with lidocaine improved radiation tolerance of both parotid and submandibular glands. The use of 12 mg/kg lidocaine was superior and displayed significant radioprotection with regard to flow sialometry and sialoscintigraphy. The ultrastructure was largely preserved after pretreatment with both lidocaine doses.
  
  
  CONCLUSIONS
  Lidocaine represents an effective radioprotective agent and a promising approach for clinical application to avoid radiation-induced functional impairment of salivary glands.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Luebeck, Luebeck, Germany. samer.hakim@mkg-chir.muluebeck.de
authors.forename: Samer George
authors.initials: SG
authors.lastname: Hakim
authors.forename: Gèza Attila
authors.initials: GA
authors.lastname: Benedek
authors.forename: Yu-xiong
authors.initials: YX
authors.lastname: Su
authors.forename: Hans Christian
authors.initials: HC
authors.lastname: Jacobsen
authors.forename: Matthias
authors.initials: M
authors.lastname: Klinger
authors.forename: Andreas
authors.initials: A
authors.lastname: Dendorfer
authors.forename: Claudia
authors.initials: C
authors.lastname: Hemmelmann
authors.forename: Birgit
authors.initials: B
authors.lastname: Meller
authors.forename: Roger
authors.initials: R
authors.lastname: Nadrowitz
authors.forename: Dirk
authors.initials: D
authors.lastname: Rades
authors.forename: Peter
authors.initials: P
authors.lastname: Sieg
mesh_terms: D000818:Animals; D004307:Dose-Response Relationship, Radiation; D005260:Female; D008012:Lidocaine / Q000494:pharmacology*; D046529:Microscopy, Electron, Transmission; D010306:Parotid Gland / Q000000981:diagnostic imaging / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure; D011817:Rabbits; D011836:Radiation Tolerance / Q000187:drug effects; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D011877:Radionuclide Imaging; D012469:Salivary Glands / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000528:radiation effects* / Q000648:ultrastructure; D012472:Salivation / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D013363:Submandibular Gland / Q000000981:diagnostic imaging / Q000187:drug effects / Q000528:radiation effects; D014463:Ultrasonography; D014987:Xerostomia / Q000209:etiology / Q000517:prevention & control
chemical_list: D011837:Radiation-Protective Agents; D008012:Lidocaine