Roles for αB-crystallin and HSPB2 in protecting the myocardium from ischemia-reperfusion-induced damage in a KO mouse model

Lisa E. Morrison, Ross J. Whittaker, Robert E. Klepper, Eric F. Wawrousek, Christopher C. Glembotski

Research output: Contribution to journalArticlepeer-review

112 Scopus citations


Overexpression studies have shown that the small heat shock proteins (sHSP) protect the myocardium from ischemia-reperfusion (I/R)-induced damage. However, gene deletion studies are necessary to demonstrate whether sHSPs are required for protection. The genes for αB-crystallin (αBC) and HSPB2, two sHSPs that are expressed in high levels in the heart, are in close proximity to one another; as a result, both genes were disrupted in a recently generated knockout (KO) mouse line. The αBC/HSPB2 KO mouse line is currently the only model that features disruption of sHSPs normally expressed in the heart. Accordingly, we examined the cardiac morphology, function, and response to I/R-induced stress in αBC-HSPB2 KO mice. Initial gross, light microscopic and echocardiographic characterization showed that the morphological and functional properties of hearts from adult KO mice were indistinguishable from age-matched wild-type (WT) mice. Electron microscopy showed that, compared with WT mouse hearts, KO mouse heart sarcomeres were relatively normal. Isolated perfused KO mouse hearts displayed normal contractility; however, when compared with WT, after I/R, KO mouse hearts exhibited a twofold reduction in contractile recovery, as well as increased necrosis and apoptosis. Additionally, when compared with WT, KO mouse hearts exhibited 43% less reduced glutathione, which is known to protect from I/R-induced damage. Thus, whereas neither αBC nor HSPB2 is essential for myocardial development and function under nonstressful conditions, one or both are required for maximal functional recovery and protection from I/R-induced necrosis and apoptosis.

Original languageEnglish (US)
Pages (from-to)H847-H855
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number3 55-3
StatePublished - Mar 2004
Externally publishedYes


  • Apoptosis
  • Glutathione
  • Knockout mouse
  • Necrosis
  • Small heat shock protein

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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