title: Facial nerve palsy after reactivation of herpes simplex virus type 1 in diabetic mice.
abstract: OBJECTIVE
  Bell's palsy is highly associated with diabetes mellitus (DM). Either the reactivation of herpes simplex virus type 1 (HSV-1) or diabetic mononeuropathy has been proposed to cause the facial paralysis observed in DM patients. However, distinguishing whether the facial palsy is caused by herpetic neuritis or diabetic mononeuropathy is difficult. We previously reported that facial paralysis was aggravated in DM mice after HSV-1 inoculation of the murine auricle. In the current study, we induced HSV-1 reactivation by an auricular scratch following DM induction with streptozotocin (STZ).
  
  
  METHODS
  Controlled animal study.
  
  
  METHODS
  Diabetes mellitus was induced with streptozotocin injection in only mice that developed transient facial nerve paralysis with HSV-1. Recurrent facial palsy was induced after HSV-1 reactivation by auricular scratch.
  
  
  RESULTS
  After DM induction, the number of cluster of differentiation 3 (CD3)(+) T cells decreased by 70% in the DM mice, and facial nerve palsy recurred in 13% of the DM mice. Herpes simplex virus type 1 deoxyribonucleic acid (DNA) was detected in the facial nerve of all of the DM mice with palsy, and HSV-1 capsids were found in the geniculate ganglion using electron microscopy. Herpes simplex virus type 1 DNA was also found in some of the DM mice without palsy, which suggested the subclinical reactivation of HSV-1.
  
  
  CONCLUSIONS
  These results suggested that HSV-1 reactivation in the geniculate ganglion may be the main causative factor of the increased incidence of facial paralysis in DM patients.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Nagoya City University Graduate School of Medical Sciences and Medical School, Nagoya, Japan; Department of Virology, Graduate School of Medicine, Nagoya University, Nagoya, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Esaki
authors.forename: Koji
authors.initials: K
authors.lastname: Yamano
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Katsumi
authors.forename: Toshiya
authors.initials: T
authors.lastname: Minakata
authors.forename: Shingo
authors.initials: S
authors.lastname: Murakami
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D004279:DNA, Viral / Q000032:analysis; D003921:Diabetes Mellitus, Experimental / Q000473:pathology* / Q000821:virology; D004195:Disease Models, Animal; D005158:Facial Paralysis / Q000473:pathology / Q000821:virology*; D005260:Female; D005434:Flow Cytometry; D005830:Geniculate Ganglion / Q000473:pathology / Q000821:virology; D006561:Herpes Simplex / Q000150:complications*; D018259:Herpesvirus 1, Human / Q000472:pathogenicity*; D051379:Mice; D008807:Mice, Inbred BALB C; D016133:Polymerase Chain Reaction / Q000379:methods; D011897:Random Allocation; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D014775:Virus Activation
chemical_list: D004279:DNA, Viral
keywords: Bell's palsy; HSV-1 reactivation; diabetes mellitus; herpes simplex virus