Effects Of Exosomes Derived From IPSC-MSCs On Repairing Osteoporotic Bone Defects In Rats And Its Related Mechanism

BACKGROUND: The formation of osteoporosis is caused by the abnormal process of osteogenesis and osteoclastogenesis.The absorption of bone is greater than the formation of bone,resulting in the reduction of bone mass,the degradation of microstructure and the destruction of microstructure.Osteoporosis in patients with bone brittleness increased and then lead to fracture of the transaction occurred.Complications are more in patients with osteoporotic fracture than normal patients,especial bone defect repair due to poor bone quality of osteoporotic patients,bone tissue delayed healing,the recovery time of patients takes longer.More attention should be paid to the treatment of osteoporosis in clinical treatment of osteoporotic fractures or bone defects,in order to reduce bone loss,promote the healing of new bone.Various clinical treatment strategies currently available for the treatment of osteoporotic bone defects are limited,such as autologous bone grafts,allogeneic bone grafts,scaffolds,and growth factors or cells,but there is still no effective way to solve this problem.exosomes derived from mesenchymal stem cell(MSCs)derived from pluripotent stem cells(i PSCs)(hi PSC-MSC-Exos)have the advantage of inducing all the advantages of pluripotent stem cells and mesenchymal stem cells and no immunogenic effects.It has been shown that the role of direct transplantation of stem cells to repair tissue is similar to that of transplanted stem cells in repairing tissue damage.However,there are no reports on the application of hi PSC-MSC-Exos to enhance angiogenesis and osteogenesis under osteoporotic conditions.OBJECTIVE: The aim of this study was to investigate the role of hi PSC-MSC-Exos in the prophylaxis and treatment of osteoporosis and to promote new bone formation under osteoporosis by enhancing the ability of angiogenesis and new bone formation in osteoporosis rats in vivo,as well as the effect of hi PSC-MSC-Exos on the proliferation and osteogenic differentiation of bone marrow MSCs derived from ovariectomized(OVX)rats(r BMSCs-OVX)and its related mechanism.METHODS: Hi PSC-MSC-Exos was extracted and identified.Different concentrations of hi PSC-MSC-Exos were transplanted into different pre-made osteoporotic rat models according to different time periods.The effect of IPSC-MSCs-exsoms on prophylaxis and treatment of osteoporosis were examined by microcomputed tomography(micro-CT)and histomorphology.The bone marrow mesenchymal stem cells of osteoporotic rats were extracted from the osteoporosis rat,which were identified by Micro CT.The targeted cells were stimulated with IPSC-MSCs-exsoms at different concentrations.The ALP activity,real-time quantitative polymerase chain reaction(RT-q PCR)and western blotting were used to detect the osteogenesis of bone marrow mesenchymal stem cells in osteob lastic rats.The effects of IPSC-MSCs-exsoms at different groups were implanted into the skull defects of osteoporotic rats.After 8 weeks,the samples were treated with Micro CT system,fluorescence confocal method,Microfil perfusion,histomorphology and immunohistochemistry to investigate the effect of IPSC-MSCs-exsoms on the repair of bone defects in osteoporotic rats by analysis.Finally,the effects of hi PS-MSCs-exsome on Wnt / β-catenin signaling pathway and osteogenic protein were detected by RT-q PCR and western blotting.RESULTS:(1)TRPS analysis and western blot analysis showed that the extracted vesicles were hi PS-MSC-Exos.(2)Transplantation of IPSC-MSCs-exsoms could significantly reduce bone loss in osteoporotic rats,(3)hi PSC-MSC-Exos can promote the proliferation of r BMSCs-OVX,and this effect has a concentration gradient-effect relationship;(4)hi PSC-MSC-Exos can promote the osteogenic differentiation of r BMSCs-OVX,and this effect has a concentration gradient-effect relationship;(5)β-TCP scaffolds+ hi PSC-MSC-Exos can more effectively improve the repair of bone defect in osteoporotic rats,(6)IPSC-MSCs-exsoms may promote osteogenic differentiation of mesenchymal stem cells by activating Wnt / β-catenin signaling pathway.CONCLUSION:(1)IPSC-MSCs-exsoms can significantly reduce the bone loss in osteoporotic rats,have the effect of antagonizing osteoporosis,and there is the higher effect in high concentration of IPSC-MSCs-exsoms.(2)IPSC-MSCs-exsoms may promote the proliferation of bone marrow mesenchymal stem cells by activating Wnt / β-catenin signaling pathway.(3)IPSC-MSCs-exsoms may promote the proliferation and osteogenic differentiation of osteoporotic bone marrow mesenchymal and this effect has a concentration gradient-effect relationship.