title: [Facial nerve injuries cause changes in central nervous system microglial cells].
abstract: BACKGROUND
  Our research group has described both morphological and electrophysiological changes in motor cortex pyramidal neurons associated with contralateral facial nerve injury in rats. However, little is known about those neural changes, which occur together with changes in surrounding glial cells.
  
  
  OBJECTIVE
  To characterize the effect of the unilateral facial nerve injury on microglial proliferation and activation in the primary motor cortex.
  
  
  METHODS
  We performed immunohistochemical experiments in order to detect microglial cells in brain tissue of rats with unilateral facial nerve lesion sacrificed at different times after the injury. We caused two types of lesions: reversible (by crushing, which allows functional recovery), and irreversible (by section, which produces permanent paralysis). We compared the brain tissues of control animals (without surgical intervention) and sham-operated animals with animals with lesions sacrificed at 1, 3, 7, 21 or 35 days after the injury.
  
  
  RESULTS
  In primary motor cortex, the microglial cells of irreversibly injured animals showed proliferation and activation between three and seven days post-lesion. The proliferation of microglial cells in reversibly injured animals was significant only three days after the lesion.
  
  
  CONCLUSIONS
  Facial nerve injury causes changes in microglial cells in the primary motor cortex. These modifications could be involved in the generation of morphological and electrophysiological changes previously described in the pyramidal neurons of primary motor cortex that command facial movements.
authors.affiliation: Laboratorio de Neurofisiología Comportamental, Departamento de Ciencias Fisiológicas, Facultad de Medicina, Universidad Nacional de Colombia, Bogotá, D.C., Colombia. jmcerong@unal.edu.co.
authors.forename: Jeimmy
authors.initials: J
authors.lastname: Cerón
authors.forename: Julieta
authors.initials: J
authors.lastname: Troncoso
mesh_terms: D000344:Afferent Pathways; D000818:Animals; D019771:Axotomy; D002455:Cell Division; D005152:Facial Muscles / Q000294:innervation; D020220:Facial Nerve Injuries / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D005158:Facial Paralysis / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D017628:Microglia / Q000473:pathology*; D009044:Motor Cortex / Q000473:pathology*; D009409:Nerve Crush; D009416:Nerve Regeneration; D017966:Pyramidal Cells / Q000473:pathology / Q000502:physiology; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
keywords: Microglial; motor cortex; pyramidal cells; rat