title: The alterations of inducible nitric oxide synthase in the mouse brainstem during herpes simplex virus type 1-induced facial palsy.
abstract: OBJECTIVE
  We sought to study the alterations of inducible nitric oxide synthase (iNOS) in the mouse brainstem during facial paralysis induced by herpes simplex virus type 1 (HSV-1) and the inhibitory effects of glucocorticoids.
  
  
  METHODS
  HSV-1 was  inoculated into the surface of posterior auricle of mouse to set up an animal model. The paralyzed mice were divided in three groups as detailed in text. Mice, in one group, were killed at different time points and, in other two groups, were injected daily for 2 days with methylprednisolone  sodium succinate (MPSS) or with combined administration of MPSS and glucocorticoid receptor blocker (RU486). Morphological changes were evaluated by means of hematoxylin and eosin (H&E) staining and improved trichrome staining. The expression and location of iNOS in the facial nucleus  of brainstem was detected by reverse transcription-polymerase chain reaction (RT-PCR), western blot, and immunohistochemistry.
  
  
  RESULTS
  After inoculated by HSV-1, 49·09% of mice developed unilateral facial paralysis. Injuries in response to HSV-1 infection in the facial nerves  and facial nucleus of paralyzed mice were observed by morphological methods. Besides, we found that iNOS was present in normal glial cells and motor neurons at low levels and was upregulated dramatically after facial paralysis, which could be inhibited by MPSS. RU486, a glucocorticoid receptor  inhibitor, could block the inhibitory effects of MPSS.
  
  
  CONCLUSIONS
  The present study demonstrates that the enhanced activity of iNOS in the early phase represents an important mechanism in HSV-1-induced facial paralysis. MPSS can effectively attenuate HSV-1-mediated damages in nerve  system, which is closely associated to its inhibitory effect on expression of iNOS.
authors.affiliation: Otolaryngology–Head and Neck Surgery, Provincial Hospital affiliated to Shandong University, Jinan, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Mao
authors.forename: Zhaomin
authors.initials: Z
authors.lastname: Fan
authors.forename: Yuechen
authors.initials: Y
authors.lastname: Han
authors.forename: Wenwen
authors.initials: W
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Jiang
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Li
authors.forename: Haibo
authors.initials: H
authors.lastname: Wang
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001933:Brain Stem / Q000201:enzymology*; D004195:Disease Models, Animal; D005158:Facial Paralysis / Q000201:enzymology / Q000473:pathology / Q000821:virology*; D006561:Herpes Simplex / Q000150:complications / Q000201:enzymology* / Q000473:pathology; D018259:Herpesvirus 1, Human; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse