Exogenous iron entered cardiomyocytes in a time- and dose- dependent manner.

<p>(<b>A</b>) Fe(III) uptake by live HL-1 cells treated at 3 indicated doses, detected by CALG-AM fluorescent assay. Fluorescence intensity was carried out by fluorescent plate reader Fusion. Local average reading at 10 min was set as initial fluorescence level. Each reading at any given time was normalized to the local initial fluorescence level. FeCl₃ was load at 30 min. Impermeant chelator DTPA was loaded at 115 min; permeant iron chelator ICL 670 was loaded at 136 min. Control was defined as treatment without addition of iron, DTPA and ICL670. (<b>B</b>) Fe(III) and Fe(II) uptake at 100 min of the assessment time point indicated in (A), i.e. 70 min after iron loading. FeCl₃ loaded with ascorbate represented Fe(II) treatment. Both controls with and without ascorbate were shown. *, †, ‡, <i>p</i><0.05; **, ††, ‡‡, <i>p</i><0.01; ***, †††, ‡‡‡, <i>p</i><0.001; * versus respective controls. The results represented as mean ± SEM of five independent triplicate experiments.