[Role of transthyretin in posttraumatic regeneration of the sciatic nerve in mouse].
Although thyroid hormones are known to have a significant influence on the development of nervous system, the absence of changes in the brain of mice deficient in transthyretin--a protein providing thyroid hormone transport across the blood-brain and blood-nerve barrier--remains unexplained. Therefore, the aim of this study was to determine the effect of transthyretin on the formation of myelinated and unmyelinated nerve fibers in sciatic nerve of mice. The myelinated and unmyelinated nerve fibers were counted in sciatic nerve of 3-months-old normal and transthyretin-knockout (transthyretin(-/-)) mice 15 and 30 days after nerve crushing. No differences were detected in the number of myelinated and unmyelinated nerve fibers in intact control (wild-type) animals group vs. transthyretin(-/-) mice. By days 15 and 30 after nerve crushing the number of myelinated nerve fibers was diminished by 54.7 and 71.8%, respectively, in transthyretin(-/-) mice, as compared to that in control animals. The number of unmyelinated nerve fibers at day 15 after the injury was not different in transthyretin(-/-) and control mice, however, by day 30 the number of these fibers in control group was found to increase significantly, exceeding that one in transthyretin(-/-) mice by 27.9%. These results indicate the important contribution of transthyretin, as a thyroxin carrier protein, to the process of posttraumatic regeneration of sciatic nerve. The absence of changes in nerve fiber numbers in transthyretin-knockout mice in postembryonic period suggests the presence of transthyretin-independent mechanism of thyroxin transport into the peripheral nervous system.
Raginov
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D000818:Animals; D051379:Mice; D018345:Mice, Knockout; D046529:Microscopy, Electron, Transmission; D009186:Myelin Sheath / Q000502:physiology*; D009412:Nerve Fibers / Q000648:ultrastructure; D009416:Nerve Regeneration / Q000502:physiology*; D011228:Prealbumin / Q000235:genetics / Q000502:physiology*; D012583:Schwann Cells / Q000648:ultrastructure; D012584:Sciatic Nerve / Q000293:injuries / Q000502:physiology* / Q000648:ultrastructure
D011228:Prealbumin