Effect of iron supplementation on CP20-, DFO-, and TPEN-induced thymocyte apoptosis.

(A) Thymocytes were preincubated for 2 hours with ferric sulfate (100 μM) prior to the addition of the iron chelators CP20 and DFO (100 μM IBE) or the zinc chelator TPEN (50 μM). The cells were spun, fixed in 70% cold ethanol, and stained with propidium iodide for apoptosis measurement by flow cytometry. The data shown are the mean ± SD of 4 independent experiments performed in triplicate. (B) Thymocytes were incubated with PBS, CP20 (300 μM IBE), TPEN (50 μM), ferric sulfate (100 μM), CP20 plus iron, TPEN plus iron, or CP20 plus iron plus TPEN for 24 hours. The cells were washed 3 times prior to the addition of zinquin (25 μM). Zinquin fluorescence was measured by spectrofluorimetry. The data shown are the mean ± SD of 4 independent experiments performed in duplicate.