Material Properties Of Degradable Alloy Fe-30Mn-0.6N And Its Effect On Ferroptosis In Synoviocytes

Objective:Fe-30Mn-0.6N is a new iron-based degradable alloy material developed by the Institute of Metals,Chinese Academy of Sciences.This study intends to elucidate the effect of Fe-30Mn-0.6N alloy on iron death of synovial cells in animals,and investigate the excellent mechanical properties,biological properties and degradation properties of Fe-30Mn-0.6N alloy to provide a theoretical basis for its application in the field of biomaterials.Methods:Fe-30Mn-0.6N alloy and Ti-6Al-4V alloy were prepared by the Medical Metallic Materials Research Laboratory,Institute of Metals,Chinese Academy of Sciences.Ti-6Al-4V alloy was used as a control.The mechanical properties of the two alloys were examined using a universal testing machine.In the in vivo experiment,36healthy clean grade New Zealand white rabbits were divided into 2 groups:Ti-6Al-4V alloy and Fe-30Mn-0.6N alloy implantation group.The implantation sites were the intercondylar and lateral condyles of the distal femur of the rabbits.The rabbits were euthanized at 2W,4W and 8W after implantation.Alloy degradation was observed using light microscopy and electron microscopy,and the deposition of elements on the alloy surface was studied with an energy spectrum analyzer.GPX4 was selected as a marker for detecting ferroptosis in synovial cells to determine the altered ferroptosis in the synovial membrane around the alloy implantation site.In in vitro experiments,the effects of different concentrations of Fe-30Mn-0.6N extract on the accumulation levels of Fe²⁺and ROS in synovial cells were studied,and the alterations of synovial cell mitochondria were observed by transmission electron microscopy.In addition,ferroptosis-related proteins such as GPX4 and SLC7A11 were determined by WB and PCR to explore the way in which iron alloy extracts affect ferroptosis in synovial cells.Results:1.Mechanical properties testing showed that Fe-30Mn-0.6N alloys exhibited tensile strength of 487±18 MPa,yield strength of 221±10 MPa,elongation of 16.9±0.3%and Young’s modulus of 37.7±1.3 GPa.2.In vivo experiments,the cross-sectional area of the Fe-30Mn-0.6N alloys decreased by 73.32±12.73%after 8 weeks of implantation.The results of SEM and EDS showed that the Fe-30Mn-0.6N alloys had more Ca,O,C and P element deposition（P<0.05）.After 2,4 and 8 weeks of implantation,no inflammatory response was observed in peri-implant synovial tissue of Fe-30Mn-0.6N and Ti-6Al-4V alloys,and Fe-30Mn-0.6N alloys did not affect the expression of the ferroptosis inhibitory gene GPX4.Compared with the control group,30%Fe-30Mn-0.6N alloy extracts did not affect the cell viability（P>0.05）in vitro,and intracellular Fe²⁺and ROS was significantly reduced（P<0.05）.WB and PCR results showed that the 30%extracts increased the protein activity and m RNA expression of GPX4,FTH1 and SLC7A11 in synoviocytes,but had no effect on PTGS2and p53.Conclusion:The biodegradable alloy material Fe-30Mn-0.6N alloy has good histocompatibility,mechanical properties and degradability without inducing significant ferroptosis in synovial cells,and may have promising applications in the field of biomaterials.