Local administration of thyroid hormones in silicone chamber increases regeneration of rat transected sciatic nerve.

Details

Serval ID
serval:BIB_6434
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Local administration of thyroid hormones in silicone chamber increases regeneration of rat transected sciatic nerve.
Journal
Experimental Neurology
Author(s)
Voinesco F., Glauser L., Kraftsik R., Barakat-Walter I.
ISSN
0014-4886 (Print)
ISSN-L
0014-4886
Publication state
Published
Issued date
1998
Peer-reviewed
Oui
Volume
150
Number
1
Pages
69-81
Language
english
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Abstract
Conflicting actions of the exogenous thyroid hormone on regenerating peripheral nerve have been reported. These contradictory results were probably due to daily intraperitoneal injections which induce a high concentration of thyroid hormone after administration. In our present study we adapted a technique which allows a local administration of thyroid hormones in a closed system. The effect of a single and local treatment with triiodothyronine (T3) on axonal growth across a gap between sectioned ends of sciatic nerve within silicone chambers was examined in Wistar rats. After nerve transection and surgical implantation, silicone chambers were filled with either a neutral pH solution of triiodothyronine dissolved in NaOH or with sterile solvent as control. Regeneration of the nerves was examined 2 to 8 weeks following the surgery. Early regeneration (4 weeks) was studied by morphological analysis of nerves which showed a significant difference between T3-treated and control groups. Morphometric analysis revealed: (1) a significant difference in the mean diameter of myelinated axons between T3-treated nerve (phi 3.80 +/- 0.22 microns) and control (phi 3.07 +/- 0.44 microns); (2) that T3 increased significantly (1.4-fold) the number of myelinated axons that grew into the middle and distal ends of regeneration chambers; (3) that ultrastructural analysis showed significantly higher percentage of myelinated axons per total axon population in T3-treated groups (38.8 +/- 5.9%) as compared to control (16.0 +/- 2.3%); and (4) that the myelinated axons had thicker myelin sheaths. The beneficial effects of T3 on regeneration, observed at 4 weeks, were sustained over a prolonged period of time. Thus, at 8 weeks of regeneration, the number, the mean diameter of myelinated axons, and the thickness of myelin sheaths remained significantly greater in T3-treated groups. Therefore, a single and local administration of thyroid hormone at the level of the transected sciatic nerve is sufficient to rapidly set off several mechanisms which, in turn, produce a stimulating and lasting effect on peripheral nerve regeneration. The beneficial effects of T3 upon injured peripheral nerve may have considerable therapeutic potential.
Keywords
Animals, Axons/drug effects, Growth Substances/administration & dosage, Growth Substances/pharmacology, Infusion Pumps, Microscopy, Electron, Myelin Sheath/drug effects, Myelin Sheath/physiology, Nerve Regeneration/drug effects, Rats, Rats, Wistar, Sciatic Nerve/drug effects, Sciatic Nerve/injuries, Silicones, Time Factors, Triiodothyronine/administration & dosage, Triiodothyronine/pharmacology
Pubmed
Web of science
Create date
19/11/2007 13:43
Last modification date
20/08/2019 15:20
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