Cardiac troponin T alterations in myocardium and serum of rats after stressful, prolonged intense exercise

Yingjie Chen, Robert C. Serfass, Shannon M. Mackey-Bojack, Karen L. Kelly, Jack L. Titus, Fred S. Apple

Research output: Contribution to journalArticlepeer-review

111 Scopus citations

Abstract

The goal of this study was to determine whether the stress of forced exercise would result in injury to the myocardium. Male rats with 8% of body weight attached to the tail were forced to swim 3.5 h (3.5S), forced to swim 5 h (5S), or pretrained for 8 days and then forced to swim 5 h (T5S). Rats were killed immediately after they swam (0 h PS) and at 3 h (3 h PS), 24 h (24 h PS), and 48 h after they swam (48 h PS). Tissue homogenates of the left ventricle were analyzed by Western blot analysis for cardiac troponin T (cTnT). Serum cTnT was quantified by immunoassay. Results indicated that, in the 3.5S, 5S, and T5S groups, serum cTnT was significantly (P < 0.01) increased at 0 and 3 h PS. The 5S group demonstrated a greater increase in serum cTnT than the 3.5S group (P < 0.01) and the T5S group (P < 0.01) at 0 h PS. Western blot analysis indicated significant decreases (P < 0.01) in myocardial cTnT in the 5S group only at 0 h PS (P < 0.01) and 3 h PS (P < 0.05). Histological evidence of localized myocyte damage demonstrated by interstitial inflammatory infiltrates consisting of neutrophils, lymphocytes, and histiocytes, as well as vesicular nuclei-enlarged chromatin patterns, was observed in left ventricle specimens from the 55 group at 24 and 48 h PS. Our findings demonstrate that stressful, forced exercise induces alterations in myocardial cTnT and that training before exercise attenuates the exercise- induced heart damage.

Original languageEnglish (US)
Pages (from-to)1749-1755
Number of pages7
JournalJournal of applied physiology
Volume88
Issue number5
StatePublished - May 1 2000

Keywords

  • Exercise stress
  • Histology
  • Myocardial damage

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