Ultrastructural changes in the rat sciatic nerve after local hyperthermia.
The rat sciatic nerve was heated over a length of 5 mm for 30 min at 43, 44 or 45 degrees C. Morphological changes were not observed after heating at 43 degrees C. Treatment at 44 degrees C resulted in endoneurial oedema and mild vascular changes, such as contraction and vacuolization of endothelial cells and thickening of the media of the larger vessels. Within 1 week several demyelinated axons were observed. The first changes after heating at 45 degrees C included oedema, blood vessel occlusion and severe endothelial cell damage. Axonal changes, e.g. the accumulation of cell organelles, appeared 8 h after treatment; 24 h after treatment most axons and myelin sheaths showed degenerative changes. Absence of blood flow in the heated area of the nerve was shown 2 h after heating at 45 degrees C. We conclude that hyperthermic treatment directly affects endothelial cells and myelin sheaths in the rat sciatic nerve. Axons degenerate most probably as a consequence of ischaemia.
Hoogeveen
J F
JF
Department of Radiotherapy, University of Amsterdam, The Netherlands.
Troost
D
D
van der Kracht
A H
AH
Wondergem
J
J
Haveman
J
J
Gonzalez Gonzalez
D
D
D000818:Animals; D001369:Axons / Q000473:pathology; D004730:Endothelium, Vascular / Q000293:injuries / Q000473:pathology; D005260:Female; D006979:Hyperthermia, Induced / Q000009:adverse effects*; D008854:Microscopy, Electron; D009186:Myelin Sheath / Q000473:pathology; D009410:Nerve Degeneration; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000293:injuries* / Q000473:pathology; D013997:Time Factors