Fig. 3

Synergistic effect of tumor necrosis factor alpha (TNFα) and H₂O₂ on induction of DNA fragmentation. (A) Rat brain capillary endothelial cells, and (B) astrocytes were grown to confluency in 96 well plates. Cells were incubated with various doses of H₂O₂ in the presence or absence of TNFα for 16 hr. At the end of the incubation, cells were stained with Hoechst 33342 and decrease of fluorescence dependent on DNA fragmentation was quantitated by a fluorescent plate reader as described in Materials and Methods. Each measurement was done in six wells and averaged. The bar graphs represent mean ± SD of three experiments performed in different cell cultures. “*” Marks significant difference between the treatments with and without TNF (p < .05).