Changes in a rat facial muscle after facial nerve injury and repair.
Muscle Nerve
; 24(9): 1202-12, 2001 Sep.
Article
in En
| MEDLINE
| ID: mdl-11494274
ABSTRACT
This study describes changes in a rat facial muscle innervated by the mandibular and buccal facial nerve branches 4 months after nerve injury and repair. The following groups were studied (A) normal controls; (B) spontaneous reinnervation by collateral or terminal sprouting; (C) reinnervation after surgical repair of the mandibular branch; and (D) chronic denervation. The normal muscle contained 1200 exclusively fast fibers, mainly myosin heavy chain (MyHC) IIB fibers. In group B, fiber number and fiber type proportions were normal. In group C, fiber number was subnormal. Diameters and proportions of MyHC IIA and hybrid fibers were above normal. The proportion of MyHC IIB fibers was subnormal. Immediate and delayed repair gave similar results with respect to the parameters examined. Group D rats underwent severe atrophic and degenerative changes. Hybrid fibers prevailed. These data suggest that spontaneous regeneration of the rat facial nerve is superior to regeneration after surgical repair and that immediacy does not give better results than moderate delay with respect to surgical repair. Long delays are shown to be detrimental.
Search on Google
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Facial Nerve Injuries
/
Facial Muscles
Limits:
Animals
Language:
En
Journal:
Muscle Nerve
Year:
2001
Document type:
Article
Affiliation country:
Suecia