Hematologic Manifestations and Changes of Cytokines or Hematopoietic Growth Factors in Mice with Iron Overlaod.

Iron overload by repeated transfusions induced organ toxicity including liver, heart. We investigated hematologic manifestations and cytokines or hematopoietic growth factors in murine secondary hemochromatosis.

We established murine secondary hemochromatosis model using 6 week-old male C57/BL6 (H-2^b) with iron dextran. Mice (n=10∼12) were intraperitoneally injected with 10 mg of iron dextran for 2 or 4 weeks. We divided five groups: control (PBS injection), iron 100mg, iron 200mg, iron 200mg with deferasirox (DFX) 300mg, and only DFX 300mg. We examined hematocrit, platelet counts and plasma iron concentration (PIC) in peripheral blood, and liver iron contents (LIC) by atomic absorption spectrophotometer. We evaluated colony forming capacity from bone marrow according to experimental group. For cytokines and hematopoietic growth factors, we performed real-time PCR for IL-1b, iNOS, IFN-g, TNF-a, TGF-b, SCF, TPO, GM-CSF, and IL-11 in bone marrow. We compared each values of relative ratio with b-actin.

There was no difference of hematocrit among experimental groups. The platelet counts were significantly decreased in iron 200mg among groups (P<0.05), and showed increased trends after administration of DFX. The levels of LIC and PIC were dependent on cumulative dose of iron loaded, and decreased by DFX (P<0.01). This findings showed positive correlation between PIC and LIC (P<0.01, R²=0.726). The CFU-GEMM and CFU-GM decreased in iron 200mg, iron 200mg+DFX300mg, and DFX300mg compared with control and iron 100mg (P<0.01). Most colonies in DFX300mg were not observed except CFU-GM. In cytokines, there was shown no difference for IL-1b, iNOS, IFN-g, TNF-a, TGF-b according to experiments (P>0.05). However, SCF was shown diminished expressions for treated mice compared with control (P=0.02). The levels of TPO were increased in hemochromatosis, and decreased after administration of DFX (P=0.05). The GM-CSF was observed significantly lower in iron 200mg, iron 200mg plus DFX, DFX than control and iron 100mg (P<0.01).

Our results suggested that iron overload might affect hematopiesis and these findings were due to effects of hematopoietic growth factors including SCF, TPO, GM-CSF, not inhibitory cytokines. Also, we need further study for DFX in hematopoiesis.

No relevant conflicts of interest to declare.