Early and late functional and histopathological perturbations in the rabbit ear-artery following local cold injury
These experiments aimed to study the in vivo short and long term neurovascular regeneration after frostbite. The rabbit central ear-artery was used as the experimental model. The effects on the noradrenergic innervation of the artery were measured in isolated vascular ring segments the first day and...
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Published in | VASA Vol. 28; no. 2; p. 85 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Switzerland
01.05.1999
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Subjects | |
Online Access | Get more information |
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Summary: | These experiments aimed to study the in vivo short and long term neurovascular regeneration after frostbite.
The rabbit central ear-artery was used as the experimental model. The effects on the noradrenergic innervation of the artery were measured in isolated vascular ring segments the first day and 2, 3-4, and 8-10 or 10-20 weeks following freezing at -9 degrees C or -18 degrees C for 15 min with slow rewarming for 7 min at room temperature.
Two days after freezing the sympathetic nerves were completely degenerated, as observed with glyoxylic acid-induced fluorescence. The vascular isometric tension responses to exogenous noradrenaline and endogenously released noradrenaline by electrical stimulation in vitro were abolished. A varying degree of necrosis of the vascular wall was observed. Two weeks after freezing at -18 degrees C in vitro responses to exogenous noradrenaline and electrical stimulation were still abolished, then gradually approaching control levels after 10-20 weeks of in vivo regeneration. Eight and 10 weeks after injury at -9 degrees C increased vascular tension responses to exogenous noradrenaline was found. In spite of a long regeneration period the total uptake and the spontaneous and K+ (75 mM) evoked releases of [3H]noradrenaline were persistently decreased after frostbite at -18 degrees C, but they were regenerated to control levels already 10-20 weeks after -9 degrees C. Regeneration of noradrenergic nerve function, expressed as [3H]noradrenaline uptake and release and responsiveness to electrical stimulation, expressed as vascular contraction, was slower than the regeneration of the vascular smooth muscle. Myointimal hyperplasia developed in response to -9 degrees C and -18 degrees C frostbite. The uptake and the K+ evoked release of [3H]noradrenaline were particularly sensitive parameters for autonomic nerve function.
The present findings may demonstrate important neurovascular reactions to local frostbite and may explain human sequelae following frostbite. |
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ISSN: | 0301-1526 |
DOI: | 10.1024/0301-1526.28.2.85 |