Effects of heme and HO on leukocyte infiltration.

Light microscopy pictures of liver sections of BALB/c mice stained with hematoxylin and eosin (H&E) (original magnification, × 40 [A,C,E,G], or × 400 [B,D,F,H]). Mice were treated for 24 hours with saline (A, B) or 750 μM heme (C, D). The lower 2 panels represent, respectively, mice pretreated for 24 hours with SnMP, followed by treatment with saline (E,F) or 750 μM heme (G,H) for 24 hours. Heme-treated mice show inflammatory lesions accompanied by leukocyte influx and liver cell injury. Animals in which HO-activity was inhibited by pharmacologic means (SnMP) show more severe inflammatory changes after heme exposure, as exemplified by larger lesions and more aggravated inflammatory cell infiltrates.