Effect of antioxidants on HKa-induced endothelial-cell apoptosis. Endothelial cells cultured on gelatin (A) or fibronectin (B) were stimulated with 10 ng/mL bFGF in the absence or presence of 50 nM HKa or 4 μM 2-ME and 150 μg/mL GSH for 12 hours. Cytoplasmic DNA was then isolated as described under “Detection of endothelial-cell apoptosis” in “Materials and methods” and analyzed using 1% agarose gel electrophoresis. Agarose gels were stained with ethidium bromide to detect fragmented DNA as a marker of apoptosis. GSH prevented DNA fragmentation caused by HKa, but not 2-ME, in cells cultured on either gelatin or fibronectin.