| 研究実績の概要 |
MC3T3-E1 and Saos2 cells were seeded at a density of 1x10*4 cells/ml and 2x10*4 cells/ml respectively on the control plate, CpTi, 3Y-TZP and NanoZr for 14 days. The cell proliferation ability was detected on Day 1, Day 4, and Day 7. It shows that both cell lines can attach and culture well on all materials. ALP ability was detected on Day 7, and Day 14. The results indicate that Saos2 cells show a better osteogenesis ability on zirconia and titanium than the control group. However, MC3T3-E1 cells could not conduct the osteogenesis ability well on all materials.
For detecting the original expression of HSPGs-riches syndecans in MC3T3-E1 and Saos2 cells. Cells were seeded at a density of 5x10*4 cells/well onto all surfaces for 24H. According to the PCR data, all syndecan members show a relatively high expression of titanium and zirconia of MC3T3-E1 cells. Interestingly, for Saos-2 cells, syndecan shows an increased expression on CpTi but a low expression on 3Y-TZP and NanoZr. The different expression levels of syndecans indicate that HSPGs might induce different mechanisms on titanium and zirconia.
Moreover, the cell mobility and cell migration of two cell lines were investigated by SEM (Scanning Electron Microscopy). A cell-free gap around 500um was set when seeding cells. After incubating for 24h, the cell-free gap was covered with two cells without any space on CpTi. On 3Y-TZP and NanoZr surfaces, cells have almost covered the gap even though a tiny space can be seen. However, the gap in the control group was not fully covered but left a smaller space around 100um-200um.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
Zirconia with excellent biocompatibility was considered a potential dental implant material. However, it still faces shortages such as low-temperature degradation and a lower osseointegration ability than titanium. Researchers have attempted to modify the zirconia surface for better cell attachment, proliferation, and differentiation in the quest to achieve more predictable osseointegration. But until now, the investigation of zirconia surface modification has not been fully understood. Last year, we screened the zirconia surface treatment-related articles and published a review discussing the surface modifications of zirconia implants to date, classified as physical treatment, chemical treatment, and surface coating. (L Sun, G Hong. Frontiers in Dental Medicine 2021) HSPG riches Syndecan promotes zirconia surface viability, we suppose that it could be used as a surface coating to improve the surface characteristics of zirconia implants in the future.
Generally, our research plan goes well within the passing year. But we still face some problems while investigating the effect of HSPG on titanium and zirconia. In the beginning, we selected three cell lines, including MG63. However, MG63 expresses unstable not only in the PCR test but also in the ALP assay. It might be due to MG63 derived from low-grade osteosarcoma and Saos2 derived from high-grade osteosarcoma. In the ALP assay, we found the osteogenesis ability was poor of MC3T3-E1 cells on all materials. It was not a result of what we expected, and finally, we suspect the problems might come from the cultural conditions.
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| 今後の研究の推進方策 |
Firstly, to improve the osteogenesis ability of MC3T3-E1 cells, the current culture medium will be replaced by a growing medium that can induce MC3T3-E1 into osteoblasts. Other candidates will be screened to verify our hypothesis with multiple cells: human primary osteoblast (hFOB); Bone mesenchymal stem cell (BMSC), which have multipotent differentiation potential capable of osteogenic differentiation and bone formation.
Based on previous findings, the syndecan family was considered a type of cell surface proteoglycans, and they appear to act as co-receptors in adhesion. Syndecans modify the downstream organization of the cytoskeleton, resulting in distinct adhesive phenotypes. As for the next step plan, we highly focused on the correlation between cell-to-material communication and the role played by the syndecan family, as well as the crosstalk between HSGP-riches syndecan and integrin.
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