Iron overload group were treated with different concentrations (0, 5, 10, 20, 40, 80 μmol/L respectively) of
ferric ammonium citrate (FAC). The control group was the group of macrophages without FAC treatment. We detected the number and state of cells, metabolic activity, the change of phagocytosis, the levels of ROS and reactive
nitrogen, and changes of related oxidative stress signaling pathways in different groups. Changes in the above indexes were detected after application of
deferasirox (DFX) to remove
iron and the
antioxidant N -acetylcysteine (NAC) to clear excess oxidative stress.
RESULTS: (1)The levels of labile
iron pool (LIP) in macrophages co-cultivated with
iron was increased with the increase of
iron concentration in a dose-dependent manner. The LIP levels was the highest in the macrophages treated with 80 μmol/L. (2)The increase of FAC concentration, the metabolic activity of macrophages in the 5 FAC-treated groups decreased to 51.58%, 40.98%, 16.23%, 3.46%, and 0.05% of the activity level of the control group (all P< 0.05). The group with the metabolic activity decreased to 16.23% (20 μmol/L) was selected as the
iron overload group for the following experiments. (3)Compared with the control group, the number of macrophages in the
iron overload group reduced to 32.80% (P<0.05), and the state of cells changed from adherence to partial
suspension. The phagocytosis of macrophages in the
iron overload group reduced to 20.40% of the control group (P<0.05). (4)Our further experiment showed that the levels of ROS and the activity
nitrogen in the
iron overload group increased by 7.71-and 1.45-fold compared with the control group (both P<0.05). The RT-PCR showed up-regulated
mRNA expression of genes related with ROS production, i. e.
nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX 4) gene related with ROS production and
inducible nitric oxide synthase (iNOS) gene related with reactive
nitrogen production, down-regulated
mRNA expression of
glutathione peroxidase 1 (GPX1) gene which participated in ROS clearance. Moreover,
mRNA expression of phosphatidylinositol-3-kinase (PI3K) gene involved in oxidative stress signaling pathway in the
iron overload group was up-regulated, while fork head
protein O3 (FOXO3) which regulated oxidative stress through negative feedback showed a down-regulation level of
mRNA expression compared with the control group. (5)After
iron chelation and
antioxidant treatment, the above-mentioned damage in the
iron overload group were partially reversed.
CONCLUSIONS: