Objective To introduce the occurrence mechanisms, prevention, and treatment measures of prosthetic aseptic loosening. Methods The recent original articles about prosthetic aseptic loosening were extensively reviewed and analyzed. Results Prosthetic aseptic loosening was a very complex process involving many mechanical and biological aspects. The main mechanical factors included prosthetic materials, shapes and sizes, implant fixation methods (including surfacetreatments), cl inical installation, interface micromotion, stress shielding, implant wear, interface integrity, and peri prosthetic high hydraulic pressure, etc.; the main biological factors included the types and sizes of wear particles, cell-activated responses, cytokine release, enzyme activation and allergic reactions to wear particles, etc.. Many measures should be adopted to effectively prevent and treat it, including improving materials and designs of prostheses, fixation techniques, surgical techniques, and drug treatments. Conclusion Prosthetic aseptic loosening is still a troublesome compl ication after joint replacements in orthopaedics, and more attention should be paid for its effective prevention and treatment.
Objective To clarify the trends of expression levels of several up-regulated micro RNA (miRNA) in tissues of atrophic bone nonunion and mRNAs and proteins of their related target genes in osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs), and to explore their biological functions. Methods The hBMSCs were isolated from bone marrow of il iac bone by gradient centrifugation, and cultured. Osteogenic culture medium was used for osteogenic differentiation of the 4th generation of hBMSCs. The changes of corresponding miRNAs, mRNA and protein expression levels of related target genes were observed at 0 hour, 12 hours, 1 day, 2 days, 4 days, 7 days, and 14 days, by quantitative real-time PCR and Western blot. Results In the process of hBMSCs osteogenic differentiation, the mRNA and protein expression levels of osteoblastic target genes [alkal ine phosphatase l iver/bone/kidney (ALPL), bone morphogeneticprotein 2 (BMP-2), and platelet-derived factor alpha polypeptide (PDGF-A)] at most time points increased significantly whencompared with the values at 0 hour except that of BMP-2 decreased at 12 hours and 1 day, with maximum changes at 1 to 7 days. The miRNA expression levels, mRNA and protein expression levels changed significantly at different time points, while the trends of hsa-miRNA-149 and hsa-miRNA-654-5p changes were negatively correlated with the trends of ALPL and BMP-2 mRNA and protein expression changes respectively (P lt; 0.05). There was no obviously negative correlation between the trends of hsa-miRNA-221 change and PDGF-A change (P gt; 0.05). Conclusion In the osteogenic differentiation process of hBMSCs, hsa-miRNA-149 and hsa-miRNA-654-5p are closely related with the mRNA and protein regulation of ALPL and BMP-2, respectively.