Induction of HO-1 inhibits the generation of ROS by LPS. Rat iBMDCs were treated with CoPP or SnPP, cultured, and incubated or not with LPS for 15 minutes. DCs were then incubated for 15 minutes with the oxidative sensitive dye CM-H2DCFDA and analyzed by cytofluorimetry. FL1-H is the log scale of fluorescence intensity. In each histogram upper numbers represent the percentage of negative (left) or positive (right) cells and the lower numbers the corresponding mean fluorescence intensity of cells. Data are representative of 3 independent experiments.