title: Stereological assessment of the total number of hypoglossal neurons after repeated crush injuries to the hypoglossal nerve in adult rats.
abstract: OBJECTIVE
  Retrograde neuronal cell death does not occur in mature motoneurons following the axonal injury of peripheral nerves. However, a previous study suggested that retrograde neuronal cell death does occur in adult rats after the creation of double lesions on the hypoglossal (XII) nerve based on a substantial decrease in the number of XII neurons. Using stereological methods, we examined neuronal apoptosis in XII neurons and the total number of XII neurons following repeated crush injuries to the XII nerve.
  
  
  METHODS
  The right XII nerve of adult rats was crushed three times at one-week intervals with a brain aneurysm clip. At 4 weeks after the final crush, the total numbers of XII neurons on the injured right and uninjured left sides were estimated stereologically.
  
  
  RESULTS
  After repeated crush injuries, no apoptosis was evident in XII neurons as indicated by immunostaining for cleaved caspase-3. Moreover, immunohistochemistry for the vesicular acetylcholine transporter revealed axonal elongation in the tongue 4 weeks after repeated crush injuries. At 4 weeks, the total numbers of XII neurons were 7800 ± 290 on the injured right side and 8000 ± 230 on the uninjured left side, and no significant difference was evident between the injured and uninjured sides.
  
  
  CONCLUSIONS
  Neuronal cell death does not occur in XII neurons and the total number of XII neurons does not decrease after repeated crush injuries of the XII nerve in adult rats.
authors.affiliation: a Department of Anatomy , Shinshu University School of Medicine , Matsumoto , Japan.
authors.forename: Nanae
authors.initials: N
authors.lastname: Fukushima
authors.affiliation: a Department of Anatomy , Shinshu University School of Medicine , Matsumoto , Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Karasawa
authors.affiliation: a Department of Anatomy , Shinshu University School of Medicine , Matsumoto , Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Yokouchi
authors.affiliation: a Department of Anatomy , Shinshu University School of Medicine , Matsumoto , Japan.
authors.forename: Norimi
authors.initials: N
authors.lastname: Sumitomo
authors.affiliation: a Department of Anatomy , Shinshu University School of Medicine , Matsumoto , Japan.
authors.forename: Kyutaro
authors.initials: K
authors.lastname: Kawagishi
authors.affiliation: a Department of Anatomy , Shinshu University School of Medicine , Matsumoto , Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Moriizumi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology; D053148:Caspase 3 / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D007839:Functional Laterality; D061228:Hypoglossal Nerve Injuries / Q000473:pathology* / Q000503:physiopathology; D009046:Motor Neurons / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D013238:Stereotaxic Techniques; D014059:Tongue / Q000473:pathology; D050494:Vesicular Acetylcholine Transport Proteins / Q000378:metabolism
chemical_list: C493461:Slc18a3 protein, rat; D050494:Vesicular Acetylcholine Transport Proteins; D053148:Caspase 3
keywords: Hypoglossal nerve; adult rats; crush injury; neuron number; neuronal cell death; stereology