Effect of reactive oxygen species mediated iron overload on murine bone marrow mesenchymal stem cells and its mechanism

Objective　To reproduce an iron overload (IO) model of murine bone marrow derived mesenchymal stem cells (BM-MSCs), explore the effects of IO on murine BM-MSCs, and elucidate the involvement of reactive oxygen species (ROS) in this process. Methods　Forty male mice (C57BL/6) were randomly divided into 4 groups (n=10): control group, IO group, Fe+iron-chelation (DFX, 125mg/kg) group and Fe+anti-oxidation (NAC, 40mmol/L) group. BM-MSCs were isolated from compact bone. The levels of iron particles, labile iron pool (LIP) and ROS in BM-MSCs were measured to confirm oxidative stress in the model. Cell proliferation was measured through population double time (DT) and by Cell Counting Kit-8(CCK-8) assay. The osteoblastic differentiation ability of BM-MSCs was assessed by alkaline phosphatase (ALP) activity, alizarin red staining and osteogenic differential genes assay. The adipogenic differentiation ability of BM-MSCs was detected by Oil-Red-O staining. Results　Compared with control group, iron deposite increased significantly with higher levels of LIP and ROS in BM-MSCs of IO group (P<0.05). In IO group, the BM-MSCs showed a longer double time than that in control group (2.07±0.14d vs 1.03±0.07d), which can be reversed to 1.52±0.07d by DFX or to 1.68±0.03d by NAC (P<0.05). IO inhibited osteogenic differentiation and mineralization of BM-MSCs, which could be attributed to decreased expression of osteogenic gene alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2) and osteocalcin (OSN). The osteoblastic differentiation ability of BM-MSCs in IO group was suppressed by IO-induced ROS upregulation. NAC or DFX treatment could partially attenuate cell injury and inhibit the signaling pathway induced by excessive iron. Conclusion　IO may impair the proliferation and differetiation ability of murine BM-MSCs by enhancing the generation of ROS. DOI: 10.11855/j.issn.0577-7402.2015.02.03