Thyroid hormones regulate skeletal muscle regeneration after acute injury

Abstract

We evaluated the effects of hypo- and hyperthyroid statuses during the initial phase of skeletal muscle regeneration in rats. To induce hypo- or hyperthyroidism, adult male Wistar rats were treated with methimazole (0.03%) or T4 (10 μg/100 g), respectively, for 10 days. Three days before sacrifice, a crush injury was produced in the solear muscles of one half of the animals, while the other half remained intact. T3, T4, TSH, and leptin serum levels were not affected by the injury. Serum T3 and T4 levels were significantly increased in hyperthyroid and hyper-injury animals. Hypothyroidism was confirmed by the significant increase in serum TSH levels in hypothyroid and hypo-injury animals. Injury increased cell infiltration and macrophage accumulation especially in hyperthyroid animals. Both type 2 and type 3 deiodinases were induced by lesion, and the opposite occurred with the type 1 isoform, at least in the control and hyperthyroid groups. Injury increased both MyoD and myogenin expression in all the studied groups, but only MyoD expression was increased by thyroidal status only at the protein level. We conclude that thyroid hormones modulate skeletal muscle regeneration possibly by regulating the inflammatory process, as well as MyoD and myogenin expression in the injured tissue.

<p>Identification of genetic variants associated with skeletal muscle function deficit in childhood acute lymphoblastic leukemia survivors</p>

“…Thyrotoxicosis is known to be a risk factor for hypercalcemia, osteoporosis and increased bone turnover 45. A study investigating correlations between thyroid hormone levels and skeletal muscle regeneration found that high serum T3 and T4 levels could interfere with the inflammatory process following muscle injuries through up-regulation of macrophage accumulation and cell infiltration 46. The detected effect of rs2001616 polymorphisms could therefore be due to up-regulation of thyroid hormone production in carriers of the variant allele.…”

Υπερηχοκαρδιογραφική Μελέτη Της Διαστολικής Λειτουργίας Της Αριστερής Και Δεξιάς Κοιλίας Σε Ασθενείς Με Υπερθυρεοειδισμό

“…43,44 Ζ παξαπάλσ «θαξδηαθή αλεπάξθεηα πςειήο παξνρήο» εκθαλίδεηαη ζπλήζσο ζε αζζελείο κηθξήο ειηθίαο κε ζνβαξφ θαη καθξνρξφλην ππεξζπξενεηδηζκφ απνπζία ππνθείκελεο θαξδηνπάζεηαο. 118,162 Έλα κηθξφ πνζνζηφ αζζελψλ, θπξίσο ειηθησκέλνη κε θνιπηθή καξκαξπγή ή ππνθείκελε θαξδηνπάζεηα, αλαπηχζζεη θαξδηαθή αλεπάξθεηα κε κεησκέλε ζπζηαιηηθφηεηα θαη θιάζκα εμψζεζεο θαη απμεκέλσλ δηαζηάζεσλ αξηζηεξή θνηιία. 27 Ζ κνξθή απηή ηεο ζπζηνιηθήο δπζιεηηνπξγίαο ζπλήζσο αληηζηξέθεηαη κε ηελ απνθαηάζηαζε ηεο ζπξενεηδηθήο ιεηηνπξγίαο.Ο ιφγνο γηα ηνλ νπνίν νξηζκέλνη αζζελείο αλαπηχζζνπλ «ππεξζπξενεηδηθή κπνθαξδηνπάζεηα» θαη πξνρσξεκέλε θαξδηαθή αλεπάξθεηα παξακέλεη άγλσζηνο.…”