Exercise training improves cardiac function-related gene levels through thyroid hormone receptor signaling in aged rats

Motoyuki Iemitsu, Takashi Miyauchi*, Seiji Maeda, Takumi Tanabe, Masakatsu Takanashi, Mitsuo Matsuda, Iwao Yamaguchi

*この研究の対応する著者

研究成果: Article査読

49 被引用数 (Scopus)

抄録

Exercise training improves the aging-induced downregulation of myosin heavy chain (MHC) and sarcoplasmic reticulum (SR) Ca2+-ATPase, which participate in the regulation of cardiac contraction and relaxation. Thyroid hormone receptor (TR), a transcriptional activator, affected the regulation of gene expression of MHC and SR Ca2+-ATPase. We hypothesized that myocardial TR signaling contributes to a molecular mechanism of exercise training-induced improvement of MHC and SR Ca2+-ATPase genes with cardiac function in old age. We investigated whether TR signaling and gene expression of MHC and SR Ca2+-ATPase in the aged heart are affected by exercise training, using the hearts of sedentary young rats (4 mo old), sedentary aged rats (23 mo old), and trained aged rats (23 mo old, swimming training for 8 wk). Trained aged rats showed improvement in cardiac function. Expression of TR-α1 and TR-β1 proteins in the heart were significantly lower in sedentary aged rats than in sedentary young rats and were significantly higher in trained aged rats than in sedentary aged rats. The activity of TR DNA binding to the transcriptional regulatory region in the α-MHC and SR Ca2+-ATPase genes and the mRNA and protein expression of α-MHC and SR Ca2+-ATPase in the heart and plasma 3,3′-triiodothyronine and thyroxine levels were altered in association with changes in the myocardial TR protein levels. These findings suggest that exercise training improves the aging-induced downregulation of myocardial TR signaling-mediated transcription of MHC and SR Ca2+-ATPase genes, thereby contributing to the improvement of cardiac function in trained aged hearts.

本文言語English
ページ(範囲)H1696-H1705
ジャーナルAmerican Journal of Physiology - Heart and Circulatory Physiology
286
5 55-5
DOI
出版ステータスPublished - 2004 5月
外部発表はい

ASJC Scopus subject areas

  • 生理学
  • 循環器および心血管医学
  • 生理学(医学)

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