Inflammation And Aseptic Loosening Induced By Ti-Mparticles Are Prevented By Al-n Particles And Proteasome Inhibitor Bortezomib

Background: The one of the important and common cause of implant failure is aseptic loosening,and granule is the main pathogenic factor of the latter.Different materials are often used in clinic for better performance.However,the biological interaction between granules of different materials is still unclear,which is very important for implant design.Purposes: The purpose of this study was to analyze the biological interactions between different types of granules and the effects of proteasome inhibitor bortezomib on granular diseases.Methods: In vitro experiments,titanium,aluminum oxide and ultrahigh molecular weight polyethylene particles were exposed to cells to simulate the process of osteolysis and inflammation induced by particles.The concentration gradient of granules in different implant materials was set,apoptosis was detected by flow cytometry,and the type and size of particles were selected to verify,meanwhile to test the therapeutic effectof bortezomib on granulosis of implants.After screening by apoptotic experiments,micron-sized titanium particles and nano-sized alumina particles were selected and further verified by MTT and light microscopy.In addition,Western blot was used to detect the expression of NF-kappa B related signal molecules,inflammatory related factors,and autophagy marker LC3 at protein level.And RT-PCR was used to detect inflammatory factors at the level of RNA.Cellular immunofluorescence and Western blot were used to detect the expression of LC3,an autophagic marker.In the animal model,C57BL/6J mice were used to construct the mouse skull osteolysis model.They were divided into five groups: control group,titanium group(Ti-?),aluminum oxide group(Al-n),titanium-aluminium oxide mixing group,titanium-aluminium oxide granule mixing group with bortezomib.Two weeks later,samples were collected,HE and immunohistochemical staining were performed in tissue and micro-CT scanning was performed in hard tissue.Results: Biological activity screening by flow cytometry showed that micron-sized titanium oxide(Ti-?)particles were more toxic to cells than that of nano-sized alumina(Al-n),meanwhile the proportion of cell death and apoptosis was higher.At the same time,through MTT in vivo,flow cytometry,immunofluorescence assay,PCR,western blot,and in vitro animal experiments such as micro-CT,hematoxylin-eosin(HE)andimmunohistochemistry,we found that Al-n initiated autophagy by blocking the activation of nuclear factor kappa B(NF-kappa B)signaling pathway and inhibited the secretion and apoptosis of inflammatory factors induced by Ti-?.In addition,bortezomib can also alleviate inflammation by blocking apoptosis and activation of NF-kappa B pathway,and significantly reduce granule-induced osteolysis in vivo.Concludes: Al-n and bortezomib can prevent granular disease caused by Ti-? and are potential effective methods for the treatment of aseptic loosening.