Effects of heme on leukocyte influx.

Leukocyte accumulation was measured by gamma camera imaging and biodistribution of ¹¹¹In-labeled leukocytes in C57Bl/6 mice. (A) Scintigraphic images of mice 21 hours after injection with either saline or heme, followed by administration of¹¹¹In-labeled leukocytes. Note that there is an increased uptake of radiolabeled leukocytes in the spleen of this heme-treated animal. (B) Effects of heme on the biodistribution of¹¹¹In-labeled leukocytes in C57Bl/6 mice 24 hours after injection. Animals treated with saline and heme are represented by white bars and black bars, respectively. Results are expressed as percentage injected dose per organ (% ID). All values are indicated as mean ± SD of 5 mice. There is a significant increase in the accumulation of radiolabeled leukocytes in the pancreas, kidneys (P < .0001), intestines, liver, brain, spleen (P < .01), and femur (P < .05) of the heme-treated animals compared to the saline-treated animals. (C) Biodistribution of ¹¹¹In-labeled leukocytes in mice 24 hours after injection corrected for weight. Animals treated with saline and heme are represented by white bars and black bars, respectively. Results are expressed as percentage of injected dose per 0.1 g tissue (% ID/0.1 g). All values are indicated as mean ± SD of 5 mice. Accumulation of radiolabeled leukocytes in the pancreas, intestines, kidneys, brain, liver (P < .01), thymus, femur, and spleen (P < .05) of the heme-treated animals were significantly increased compared to levels in the saline-treated animals.