High level of Trx prevents I/R-induced mitochondrial cristae and DNA damage. (A) Ultrastructural analysis of sham or I/R hearts from NT, Trx-Tg and dnTrx-Tg. Representative transmission electron microscopic images showing cristae structure and density. Calculated cristae density (B), percent damaged mitochondria (loss of ≥50% cristae density) (C), and width of mitochondria (D) and plotted as bar graph. Values are means ± SD (n = 25). *, p < 0.01 versus Sham; **, p <0.01 versus NT or Trx-Tg IR.