title: Degenerative and protective reactions of the rat trigeminal motor nucleus after removal of the masseter and temporal muscles.
abstract: BACKGROUND
  Microsurgical reconstruction techniques have allowed treatment of advanced head and neck carcinomas; however, it remains difficult to achieve long-term, functional reconstruction of the faciocervical muscles. To address this issue, in this we developed a rat trigeminal nerve denervation model that closely simulates the effects of oral surgery.
  
  
  METHODS
  The rat trigeminal nerve denervation model was developed by removing the masseter and temporal muscles, and degeneration process of the trigeminal motor nucleus was investigated by immunohistochemistry with particular focus on microglial/astrocytic reactions and motoneuron degeneration.
  
  
  RESULTS
  Atrophy of the trigeminal motor nucleus was observed at 8 weeks after denervation. A microglial reaction peaked at 3 days post-operation, while an astrocytic reaction was evident within 2 weeks, and peaked around 4 weeks post-operation. Expression of the stress protein HSP27 and an autophagy marker Rab24 was also upregulated in the injured trigeminal motor nucleus.
  
  
  CONCLUSIONS
  The results from this study suggest that this model is a practical and useful tool help to develop a further understanding of the pathology of the trigeminal motor nucleus after surgical denervation.
authors.affiliation: Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Seki
authors.forename: Satoshi O
authors.initials: SO
authors.lastname: Suzuki
authors.forename: Seiji
authors.initials: S
authors.lastname: Nakamura
authors.forename: Toru
authors.initials: T
authors.lastname: Iwaki