title: Effects of corticosteroids on functional recovery and neuron survival after facial nerve injury in mice.
abstract: OBJECTIVE
  To assess the effects of corticosteroid administration on functional recovery and cell survival in the facial motor nucleus (FMN) following crush injury in adult and juvenile mice and to evaluate the relationship between functional recovery and facial motoneuron survival.
  
  
  METHODS
  A prospective blinded analysis of functional recovery and cell survival in the FMN after crush injury in juvenile and adult mice was carried out. All mice underwent a unilateral facial nerve crush injury and received 7 doses of daily injections. Adults received normal saline or low-dose or high-dose corticosteroid treatment. Juveniles received either normal saline or low-dose corticosteroid treatment. Whisker function was monitored to assess functional recovery. Stereologic analysis was performed to determine neuron and glial survival in the FMN following recovery.
  
  
  RESULTS
  Following facial nerve injury, all adult mice recovered fully, while juvenile mice recovered slower and incompletely. This corresponded to a significantly greater neuron loss in the FMN of juveniles compared with adults. Corticosteroid treatment slowed functional recovery in adult mice. This corresponded with significantly greater neuron loss in the FMN in corticosteroid-treated mice. In juvenile mice, corticosteroid treatment showed a trend, which was significant at several time points, toward a more robust functional recovery compared with controls.
  
  
  CONCLUSIONS
  Corticosteroid treatment slows functional recovery and impairs neuron survival following facial nerve crush injury in adult mice. The degree of motor neuron survival corresponds with functional status. In juvenile mice, crush injury results in overall poor functional recovery and profound cell loss in the FMN. With low-dose corticosteroid treatment, there is a significantly enhanced functional recovery after injury in these mice (P < .05).
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, Stanford University, 801 Welch Road, Stanford, CA 94305, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Lieberman
authors.forename: Taha A
authors.initials: TA
authors.lastname: Jan
authors.forename: S Omar
authors.initials: SO
authors.lastname: Ahmad
authors.forename: Sam P
authors.initials: SP
authors.lastname: Most
mesh_terms: D000367:Age Factors; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005154:Facial Nerve / Q000166:cytology / Q000502:physiology; D020220:Facial Nerve Injuries / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D005938:Glucocorticoids / Q000008:administration & dosage / Q000494:pharmacology*; D007958:Leukocyte Count; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009457:Neuroglia / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D011446:Prospective Studies
chemical_list: D000893:Anti-Inflammatory Agents; D005938:Glucocorticoids; D003907:Dexamethasone