Iron overload induced osteocytes apoptosis and led to bone loss in Hepcidin

Numerous studies have demonstrated that iron overload is a risk factor of osteoporosis. However, there has been no systematic and in-depth studies on the effect of iron overload on osteocytes and its role in iron overload-induced bone loss. Therefore, to address this problem, we carried out in vitro and in vivo studies using MLO-Y4 osteocyte-like cells and Hepcidin(1) MLO-Y4 cells were treated with ferric ammonium citrate (FAC). Intracellular reactive oxygen species (ROS) levels and apoptosis of MLO-Y4 cells were determined by flow cytometry. Western blotting was performed to evaluate the effect of FAC on the expression of sclerostin and RANKL/OPG. (2) The conditioned medium of MLO-Y4 cells after treatment with FAC was collected and used to treat pre-osteoblasts and monocytes. Alkaline phosphatase (ALP) staining and alizarin red (AR) staining were used to evaluate osteogenic differentiation capacity, and tartrate-resistant acid phosphatase (TRAP) staining was performed to demonstrate osteoclast differentiation capacity. (3) In vivo studies included a wild type mouse, Hepcidin(1) FAC increased intracellular ROS and apoptosis in MLO-Y4 cells, while FAC enhanced the expression of sclerostin and RANKL/OPG in MLO-Y4 cells. (2) Conditioned medium of MLO-Y4 cells inhibited the osteogenic capacity of osteoblasts while stimulating osteoclast differentiation. (3) By increasing oxidative stress, iron overload promotes the apoptosis of osteocytes and undermines the morphology of osteocytes in HepcidinOsteocyte apoptosis due to increased ROS and resultant sclerostin and RANKL/OPG expression alteration was the main reason for bone loss in Hepcidin