Study Of Osteointegration Promoted By Silicon Nanoparticles Ti Surface

Part I The adhesion and proliferation of bone marrow-derivedmesenchymal stem cells promoted by nanoparticles surface[Abstract] Objective This study aim consists on evaluation of adhesion andproliferation of rat bone-marrow derived mesenchymal stem cells (MSCs) on nanoparticlesTitanium (Ti) surface. Method Passage3MSCs were respectively seeded on nanoparticlesTi surface and pure Ti surface, then cultured for32hours. Cell morphology and viabilitywere separately examined by scanning electron microscopy (SEM) and3-(4,5-Dimethylthiazsol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Moreover,mitotic rate of attached MSCs was observed through immunocytochemistry. And real-timepolymerase chain reaction (Real-time PCR) was applied to determine the adhesionassociated messenger ribonucleic acid (mRNA), CD44gene encoding variant isoform6(CD44V6) and Integrinβ1level. Results MSCs performed better in faster extension onnanoparticles Ti surface than on pure Ti surface after cultured for4hours, and werequicker in fusion patterns after16hours. Furthermore, cell viability was significantlyincreased on nanoparticles Ti surface compared with pure Ti surface16hours after initialseeding (P<0.05), and the mitotic rate of attached MSCs on nanoparticles Ti surface washigher than that on pure Ti surface after32hours (P<0.05). More interestingly, the CD44V6and Integrinβ1mRNA in nanoparticles Ti surface group expressed higher than that inpure Ti surface group after4hours (P<0.05), and positive correlation between CD44V6and Integrinβ1was found through statistical analysis (correlation coefficient rs=0.98,P<0.05). Conclusion Our study result indicates that nanoparticles Ti surface cansignificantly promote the adhesion and proliferation of MSCs, and improve the bioactivityof Ti surface. Part II Effects of silicon nanoparticles titanium surface on osteogenicdifferentiation of rat bone marrow mesenchymal stem cells[Abstract] Objective In this in vitro study, we investigated the effects of silicon (Si)nanoparticles titanium (Ti) surface on osteogenic differentiation of rat bone marrowmesenchytmal stem cells (MSCs). Method Passage3MSCs were respectively cultured onpure Ti surface and Si nanoparticles Ti surface for12days. The cell viability ofproliferation and osteogenic differentiation were detected with Cell Counting Kit-8assay,fluorescence microscopy and Western Blotting. Furthermore, the soaking solution of Sinanoparticles Ti surface on MSCs' mineralization was analyzed by alizarin red S stainingand quantitative determination. Results The results showed proliferation of MSCs on Sinanoparticles Ti surface was stronger than that on pure Ti surface. Alkaline phosphatasesecretion, expressions of collagen I and osteocalcin and MSCs' mineralization showed tobe significantly higher on Si nanoparticles Ti surface than those on pure Ti surface.Conclusion These findings fundamentally support the use of Si nanoparticles Ti coating insurface modification of medical Ti implant. Part III Study of a novel rat model for total knee arthroplasty[Abstract] Objective The purpose of this experiment is to design and perform a totalknee arthroplasty with titanium cementless prosthesis in rats to explore the feasibility of anew total knee arthroplasty model in rats. Methods21SD rats, weight300to325g, wererandomly divided to knee arthroplasty group, sham operation group and nonfunctionalgroup (n=7). Animals in each group underwent surgical treatment. Rats in the kneearthroplasty group were implanted with prosthesis of titanium screw between the femoralcondyles and sutured according to difference layers. After femoral articular surface wasexposured along medial side of right patellar and tendon, incision was sutured in layers inthe sham operation group. In the nonfunctional group, distal femur was exposed alongpatellar and tendon, and removal of patellar tendon, knee meniscus, anterior cruciateligament and lateral collateral ligament was done before incision was sutured in layers.Pain-related behaviors of rats were assessed within4weeks postoperation, degree of theright knee movement was check, and X-ray examination of knee was performed every week postoperation. All values were expressed as mean±standard deviation. SPSS12.0package was used to process experimental data, t test or one-way analysis of variance(ANOVA) was accordingly used for analysis and multiple comparisons of the data. P<0.05means difference was statistically significant. Results Food intake and walking andstanding index were not statistically significant difference between the sham group and theknee arthroplasty group within4weeks postoperation. However, both of these two groupswere better than the nonfunctional group as the walking and standing index was concernedone week postoperation (P<0.05). No significant difference of passive knee activity waspostoperatively detected among the three groups. X-ray images showed that the prosthesiswas in adequate position, and no sign of osteolysis was around the prosthesis in the kneearthroplasty group. Conclusion The experimental design and procedure of artificial kneereplacement in rat model is convenient, providing good function of postoperative activity,and can be used for the experimental study of simulated clinical knee arthroplasty. Part IV Mechanical stability and osteointegration of siliconnanoparticles titanium implants in a rat model of knee arthroplasty[Abstract] Objective To compare two different prosthetic materials' bioactivities,titanium and silicon nanoparticles titanium were respectively implanted into a kneearthroplasty model of rat to observe load-bearing mechanical stability and osseointegrationof their surfaces. Methods The titanium and silicon nanoparticles titanium prosthesis wereimplanted into the rats knee joints, and three days later, micro-particles of ultra-highmolecular weight polyethylene(UHMW-PE) were injected in the operative knee jointcavities every week to induce aseptic inflammation. All of the animals were sacrificed inpostoperative month. The postoperative changes of the position of the prosthesis andsurrounding bone were observed through X-ray films captured every week. Pull-out testwas used to assess the mechanical stability of the prosthesis. Reconstruction of the distalfemur bone after the prosthesis being moved was performed through micro-computedtomography (Micro-CT) scan. Histopathological bone around the prosthesis, change ofbone trabecula and aseptic inflammation were observed under microscopy. SPSS12.0package was used to process experimental data, t test or one-way analysis of variance(ANOVA) was accordingly used for analysis and multiple comparisons of the data. P<0.05 means difference was statistically significant. Results The titanium and siliconnanoparticles titanium prosthesis did not sink in each group, indicating that both prosthesesare mechanically stable and were not loosening. However, the bone integration on siliconnanoparticles Ti group was enhanced, which could be reflected by the anti-pull-outstrength in silicon nanoparticles Ti group was significantly stronger than that in titaniumgroup(P<0.05). There existed more periprosthetic new bone formation in siliconnanoparticles Ti group than that in the osteolysis induction titanium group. The osteoblastcell proliferation could be observed in the silicon nanoparticles Ti group, and no obviousinflammatory cell infiltration was detected. Conclusion The surface of the siliconnanoparticles titanium is more conducive to osseointegration than the titanium surfacefrom observation in the model of rat knee arthroplasty. Such surface reduces asepticinflammation induced by polyethylene micro-particles. When biological prostheticarthroplasty is considered, this study provides foundation for recommended selection forthe modification of titanium prosthesis with silicon nanoparticles surface.