Background: We constructed an animal model to examine the possibility that erythrophagocytosis may contribute to decreased hemoglobin (Hgb) levels in acute infection in mice.
Methods: BALB/c mice weighing 20 to 25 g were injected (intraperitoneally) with lipopolysaccharide (LPS) (Escherichia coli serotype) of some concentrations. Control mice were injected intraperitoneally with saline (0.5 mL). Two and 4 hours after LPS administration, mice were bled (0.25 mL) for complete blood count measures and tumor necrosis factor-α and interleukin-6 levels. The mice were then killed, and their spleen, liver, and bone marrow were examined microscopically for erythrophagocytosis.
Results: After LPS administration, mouse Hgb and hematocrit levels dropped significantly. At 4 hours after LPS injection, all Hgb and hematocrit concentrations were found to be significantly lower compared with that of controls (P=0.002 and 0.001, respectively). Significantly increased concentrations of tumor necrosis factor-α and interleukin-6 were evident after LPS injection. Prominent hepatic erythrophagocytosis was observed in the LPS-injected mice compared with controls. A significant across-group difference was observed at 4 hours, driven by significantly higher values in group 500 mcg versus controls (P=0.005) and 100 mcg (P=0.025). A significant increase in erythrophagocytes was observed at 2 to 4 hours in the 500 mcg LPS group (P=0.044).
Conclusions: Erythrophagocytosis may play a role in anemia associated with acute infection in mice.