Figure 4.

Cytotoxicity toward neutrophils of HUVECs exposed to H₂O₂. (A) A representative photomicrograph of neutrophils cultured for 16 hours with 100 μM H₂O₂-pretreated HUVECs and stained with diaminobenzidine and Giemsa solutions. Arrows point to apoptotic neutrophils with condensed and/or fragmented nuclei and cytoplasm positively stained with diaminobenzidine (brown in the original photograph). Original magnification, × 1000. (B) The number of apoptotic neutrophils co-cultured with HUVECs exposed to or not exposed to H₂O₂. Data are reported as the means ± SEM of values obtained from 5 experiments. *p < 0.05 vs. cells not exposed to H₂O₂.