Isoproterenol-induced cardiotoxicity in Sprague-Dawley rats: Correlation of reversible and irreversible myocardial injury with release of cardiac troponin T and roles of iNOS in myocardial injury

Jun Zhang, Alan Knapton, Steven E. Lipshultz, James L. Weaver, Eugene H. Herman

Research output: Contribution to journalArticle

74 Scopus citations

Abstract

The present study was undertaken to characterize myocardial lesions in the rat induced by low doses of isoproterenol (Iso) and to correlate lesion severity with release of cardiac troponin T (cTnT) and changes in myocyte iNOS expression. Two types of cardiac injury patterns were observed. A Type I response, noted 3 or 6 hours postdosing with 8, 16, 32, or 64 μg/kg Iso, included potential reversible myocardial alterations associated with slight increases in serum cTnT (< 0.3 ng/mL) and a slight reduction in myocyte cTnT immunoreactivity. The second type of response noted 3, 6, 12, 24 or 48 hours postdosing with 125, 250, or 500 μg/kg Iso consisted of irreversible myocyte alterations, together with significant increases in serum cTnT (3-14 ng/mL) and a marked reduction of cTnT immunoreactivity. By 48 hours the hearts of rats dosed with 125-500 μg/kg Iso had developed interstitial fibrosis, and serum cTnT had declined to near control levels (0.06-0.18 ng/mL). Increases in iNOS immunoreactivity correlated with the lesion severity. These findings suggest that low doses of Iso exert complex effects on the myocardium and that the generation of NO through increased expression of iNOS could be an important factor in the pathogenesis of myocyte injury.

Original languageEnglish (US)
Pages (from-to)277-288
Number of pages12
JournalToxicologic Pathology
Volume36
Issue number2
DOIs
StatePublished - Feb 1 2008

Keywords

  • Cardiac troponins
  • iNOS
  • Myocardial apoptosis
  • Myocardial necrosis

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Toxicology
  • Health, Toxicology and Mutagenesis

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