Figure 1.

Cardiomyocytes surviving H₂O₂ treatment show abnormal mitochondrial morphology. Neonatal rat cardiomyocytes were treated with 300 μM H₂O₂ or equivalent volume of PBS for 2 h and kept under tissue culture condition for 24 h before recording for morphology (A) or analyses of mitochondrial morphology (B, C). Cells seeded on glass coverslips were stained with MitoTracker Deep Red 633 as described in Materials and Methods (B). The images were acquired by Olympus DP72 digital camera attached to Olympus BX53 fluorescent microscope (B). Cells were fixed in phosphate-buffered 2.5% glutaraldehyde (pH 7.4) followed by osmium tetraoxide prior to resin embedment for electron microscopy (EM) (C). A representative image from ×31,000 amplification is shown for control or H₂O₂-treated cardiomyocytes (C).