title: Degeneration and regeneration of motor and sensory nerves: a stereological study of crush lesions in rat facial and mental nerves.
abstract: The aim of this study was to evaluate the degeneration and regeneration of a sensory nerve and a motor nerve at the histological level after a crush injury. Twenty-five female Wistar rats had their mental nerve and the buccal branch of their facial nerve compressed unilaterally against a glass rod for 30s. Specimens of the compressed nerves and the corresponding control nerves were dissected at 3, 7, and 19 days after surgery. Nerve cross-sections were stained with osmium tetroxide and toluidine blue and analysed using two-dimensional stereology. We found differences between the two nerves both in the normal anatomy and in the regenerative pattern. The mental nerve had a larger cross-sectional area including all tissue components. The mental nerve had a larger volume fraction of myelinated axons and a correspondingly smaller volume fraction of endoneurium. No differences were observed in the degenerative pattern; however, at day 19 the buccal branch had regenerated to the normal number of axons, whereas the mental nerve had only regained 50% of the normal number of axons. We conclude that the regenerative process is faster and/or more complete in the facial nerve (motor function) than it is in the mental nerve (somatosensory function).
authors.affiliation: Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Oral and Maxillofacial Surgery, University of Gothenburg, Sweden.
authors.forename: Z
authors.initials: Z
authors.lastname: Barghash
authors.forename: J O
authors.initials: JO
authors.lastname: Larsen
authors.forename: A
authors.initials: A
authors.lastname: Al-Bishri
authors.forename: K-E
authors.initials: KE
authors.lastname: Kahnberg
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001369:Axons / Q000473:pathology; D002467:Cell Nucleus / Q000473:pathology; D002680:Chin / Q000293:injuries / Q000294:innervation*; D005154:Facial Nerve / Q000033:anatomy & histology* / Q000166:cytology / Q000503:physiopathology; D020220:Facial Nerve Injuries / Q000503:physiopathology*; D005260:Female; D009409:Nerve Crush / Q000009:adverse effects*; D009416:Nerve Regeneration / Q000502:physiology*; D010525:Peripheral Nerves / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar
keywords: crush lesion; facial nerve; mental nerve; nerve regeneration; rat; stereology