| Project/Area Number |
17591996
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Conservative dentistry
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| Research Institution | Nagasaki University |
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Principal Investigator |
IKEDA Takeshi Nagasaki University, University Hospital of Medicine and Dentistry, Instructor, 医学部・歯学部附属病院, 助手 (90244079)
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| Co-Investigator(Kenkyū-buntansha) |
YNAGIGUCHI Kajirou Nagasaki University, University Hospital of Medicine and Dentistry, Assistant professor, 医学部・歯学部附属病院, 講師 (50264255)
OHARA Naoko Nagasaki University, Graduate School of Biomedical-Sciences, Instructor, 大学院医歯薬学総合研究科, 助手 (80301365)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | chitosan / hard tissue regeneration / bone marrow-derived progenitor cells / cDNA microarray / ALP / osteocalcin / BMP- / real-time PCR / 培養骨芽細胞 |
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| Research Abstract |
The present study was designed to investigate histochemically the biodegradation processes of chitin and chitosan implanted in rat alveolar bone. Lysozyme was immunohistochemically detected using postembedding immunogold labeling. The degradation process was ultrastructurally observed using the lectin-colloidal gold technique with electron microscopy. Three groups of chitin were specially prepared according to their degree of deacetylation : 100% deacetylated chitin (DDAC 100) ; 50% (DDAC 50) ; and 0% (DDAC 0). The present immunohistochemical study indicated that lysozyme expression was not detected in the DDAC 100 group. Furthermore, electron microscopy clearly demonstrated that the contour of implanted chitosan changed over time, and that chitosan-like fragments were present in the phagosomes in the DDAC 50 and 100 groups. These findings strongly suggest that phagocytes, such as multinuclear cells, are easily supplied in bone tissue and that the phagocytosis is more effective than en
… More
zymatic digestion for chitin and chitosan biodegradation in bone tissue. DDAC 100 should be a suitable biomaterial for bone surgery and bone regeneration therapy.
The other study was undertaken to evaluate the applicability of chitosan monomer (D-glucosamine hydrochloride) as a pulp capping medicament. Both in vitro and in vivo experiments were carried out to study the cell metabolism and wound healing mechanisms following the application of chitomonosaccharide. After 3 days of osteoblast culture, alkaline phosphatase (ALP) activity significantly increased in the chitosan group. Reverse transcription polymerase chain reaction analysis revealed that chitosan induced an increase in the expression of ALP mRNA after 3 days and bone morphogenetic protein-2 mRNA after 7 days of osteoblast incubation. Inflammatory cytokine, interleukin (IL)-8, synthesis in fibroblasts was strongly suppressed in the medium supplemented with chitosan monomer. Histopathological effects were evaluated in rat experiments. After 1 day, inflammatory cell infiltrations were observed to be weak when compared with the application of chitosan polymer. After 3 days, a remarkable proliferation of fibroblasts was seen near the applied chitosan monomer. The inflammatory cell infiltration had almost completely disappeared. After 5 days, the fibroblastic proliferation progressed, and some odontoblastic cells appeared at the periphery of the proliferated fibroblasts. These findings indicate that the present study is the first report that chitosan monomer acts as a biocompatibly stable medicament even at the initial stage of wound healing in comparison with the application of chitosan polymer. Less
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