The specimens of femur from wild-type mice(WT) of 6 months and Hepcidin-knockout(KO) mice of 6 months(iron accumulation model) were obtained for Micro-CT examination. Western blot and co-immunoprecipitation were used to detect the changes of related parameters in Wnt signaling pathway. Compared with wild-type mice, the bone mass in Hepcidin-KO mice was significantly decreased, the binding of β-catenin to FOXO3a increased, and binding of β-catenin to TCF4/TCF7L2 decreased in bone tissue, without significant changes in the expression of β-catenin, TCF4/TCF7L2, and FOXO3a. These results suggest that iron accumulation may affect bone formation through interfering with canonical Wnt/β-catenin signaling pathway, finally leading to osteoporosis.

Objective:Based on Web of Science database, this study aimed to explore the current status, research hotspots and development trends of countries regarding clinical management of osteoporotic fractures using bibliometrics and visualized analysis.Methods:We collected literatures in the field of clinical management of osteoporotic fractures included in Web of Science database, and applied bibliometrics to analyze the publication dates, countries, institutions, journals, authors, highly cited literatures and research hotspots. Visualization was drawn by VOSviewer software.Results:Analysis of the 2 508 articles revealed 3 types of data. (1) The analysis of basic information of the literature showed that: ①The country with the largest number of publications was the United States, which published 672 articles, followed by the United Kingdom and Canada, and China ranked fourth; ②The top three authors in the number of publications were Kanis JA, Cooper C and McCloskey EV respectively; ③The institution with the highest number of publications was the University of Sheffield, UK, followed by the University of Southampton, UK and the University of Toronto, Canada. (2) Network visualization of highly cited literatures showed that 118 highly cited literatures were mainly divided into 5 clusters, which were related to osteoporotic fracture diagnosis, treatment, medication adherence, management consensus and strategies of preventing refracture. (3) Temporal overlay visualization of research hotspots showed that early research mainly focused on traditional therapeutic drugs, and current research hotspots were mainly molecular targeted drugs, trabecular bone score and fracture liaison services.Conclusion:This study shows that the research activity of clinical management of osteoporotic fractures is increasing worldwide, and there is still a huge gap between China and Europe or the United States. Current research hotspots and development trends mainly focus on molecular targeted drugs, osteoporotic fracture treatment concepts, emerging fracture risk assessment tools, and fracture prevention and management models.

Objective: To investigate the effect of endogenous iron accumulation onbone mass, intraosseous vessels and the effect of exogenous iron on endothelial cell activity. Methods: The mice were divided into control group (C57/BL6 mice without hepcidin knockout) and hepcidin-knockout group (10 mice in each group, 8 weeks old and weighing about 22 g). The mice in both groups were killed at the age of 16 weeks. Serum ferritin levels were measured by Enzyme-linked immunosorbent assay (ELISA), and iron accumulation in liver tissue was measured by Prussian blue staining, while femoral micro-structure was measured by micro-CT, and H-type vessel immunofluorescence staining was used to detect the number of H-vessels in bone. Cell experiments were divided into normal culture group (normal cell group) and intervention group (Fe group) with 200 μmol/L ammonium ferric citrate. Scratch test was used to detect the migration ability of vascular endothelial cells, and tube formation test was used to detect the function of vascular endothelial cells. The endothelial activity of vascular endothelial cells was detected by immunofluorescence. Results: The level of serum ferritin (318.30±12.53 ng/ml) in the hepcidin-knockout group was significantly higher than that in control group (109.60±4.66 ng/ml). The percentage of blue area of Prussian liver iron staining in the hepcidin-knockout group (80.80%±3.156%) was significantly higher than that in control group (20.94%±2.813%). Bone mineral density in the hepcidin-knockout group (0.044±0.002 mg/m³) was significantly higher than that in control group (0.131±0.008 mg/m³). The number of intraosseous blood vessels in the hepcidin-depleted mice (17.06%±1.060%) was significantly lower than that in control group (38.76%±4.576%). There were significant differences between the two groups in each index (t=-49.367,-13.788, 35.293, 6.165; all P < 0.05). The scratches of vascular endothelial cells in Fe group were reduced by 24.300%±1.849% after 24 hours of culture, which was significantly lower than that in normal group (39.060%±3.211%). The area of vascular endothelial cells in Fe group (0.035±0.003 mm²) was significantly lower than that in normal group (0.330±0.018 mm²). The EMCN positive cells of vascular endothelial cells in Fe group were significantly lower than those in normal group. The percentage of cell number (12.000%±3.462%) was significantly lower than that of normal cell group (0.035%±0.003%). There were significant differences in cell indices between the two groups (t=9.790, 18.929, 13.922; all P< 0.05). Conclusion Endogenous iron accumulation aggravated bone loss in mice, and the number of intraosseous blood vessels decreased significantly. Vascular endothelial cells were inhibited by iron intervention in migration, tube-formation and endothelial ability.