title: Quantitative analysis of muscle histologic method in rodent facial nerve injury.
abstract: OBJECTIVE
  To describe denervation features of facial musculature following facial nerve injury in a rodent model.
  
  
  METHODS
  Six Wistar-Hannover rats underwent unilateral transection and immediate repair of the facial nerve. After 8 weeks, muscular bundles consisting of dilator naris and levator labii superioris from both sides were analyzed for mean muscle cell diameter and the percentage of muscle cell cross-sectional area using image processing software. The atrophic features of facial muscles were quantified and compared with the contralateral, healthy side of the face.
  
  
  RESULTS
  Weekly postoperative whisking assessment demonstrated the anticipated course of recovery. We observed significant differences between the normal side and the manipulated side, respectively, in the percentage of muscle specimen cross-sectional area attributable to muscle cell profiles (57% vs 29%; P = .006) and total fiber counts (1346 vs 794; P = .02). The mean cross-sectional area of individual muscle fibers was higher on the normal side (1129 vs 928 μm2; P = .39); however, this difference was statistically nonsignificant.
  
  
  CONCLUSIONS
  The objective, quantitative measures of muscle microstructure used in this report provide a valuable point of comparison for whisking function and electrophysiologic measures and can be used in future studies to assess muscle atrophic features associated with facial nerve injury and repair techniques.
authors: Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02114, USA. Tessa_Hadlock@meei.harvard.edu
authors: Tessa A
authors: TA
authors: Hadlock
authors: Sang W
authors: SW
authors: Kim
authors: Julie S
authors: JS
authors: Weinberg
authors: Christopher J
authors: CJ
authors: Knox
authors: Marc H
authors: MH
authors: Hohman
authors: James T
authors: JT
authors: Heaton
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005152:Facial Muscles / Q000294:innervation* / Q000473:pathology*; D020220:Facial Nerve Injuries / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D008866:Microsurgery; D009119:Muscle Contraction / Q000502:physiology; D009121:Muscle Denervation; D009133:Muscular Atrophy / Q000473:pathology* / Q000503:physiopathology; D009416:Nerve Regeneration / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D014738:Vibrissae / Q000294:innervation