Vibration exposure and peripheral nerve fiber damage.
The hind leg of adult rats was exposed to vibrations (82 Hz; amplitude peak-to-peak 0.21 mm) for 4 hours during 5 consecutive days. Light and electron microscopic examination of the plantar and sciatic nerves were done immediately after the exposure period or after a 2- or 4-week recovery period. Light microscopic examination did not reveal any distinct signs of injury. However, ultrastructurally unmyelinated fibers in the plantar nerves showed distinct changes, with deranged axoplasmic structure and/or accumulation of smooth endoplasmatic reticulum. These changes were to a large extent reversible in 2 weeks and appeared normalized after a 4-week recovery period. No ultrastructural changes could be observed in the sciatic nerve. However, when the sciatic nerve was crushed after 5 days of vibration exposure, axonal outgrowth was increased 23% as compared with controls. These findings confirm that vibration induces nerve fiber damage, in this experimental model expressed as a "conditioning effect" contributing to increased regeneration potential of the corresponding neurones.
Lundborg
G
G
Department of Hand Surgery, University of Lund, Malmö General Hospital, Sweden.
Dahlin
L B
LB
Hansson
H A
HA
Kanje
M
M
Necking
L E
LE
D000818:Animals; D008854:Microscopy, Electron; D009412:Nerve Fibers / Q000473:pathology / Q000648:ultrastructure; D010523:Peripheral Nervous System Diseases / Q000209:etiology; D051381:Rats; D011919:Rats, Inbred Strains; D012584:Sciatic Nerve / Q000293:injuries* / Q000648:ultrastructure; D014732:Vibration / Q000009:adverse effects*