| Co-Investigator(Kenkyū-buntansha) |
MITANI Hideo TOHOKU UNIV., SCHOOL OF DENT., PROFESSOR, 歯学部, 教授 (50014220)
KAGAYAMA Manabu TOHOKU UNIV., SCHOOL OF DENT., PROFESSOR, 歯学部, 教授 (60004610)
SHIMIZU Yoshinobu TOHOKU UNIV., SCHOOL OF DENT., ASSOCIATE PROFESSOR, 歯学部, 助教授 (20005078)
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| Research Abstract |
1.Osteoblast-like cells, MC3T3-El or periodontal-ligament derived fibroblasts were cultured on Type I collagen-coated silicon membranes and subjected to cyclic mechanical stimulation. The cells assumed a spindle shape, and the cytoskeleton components, including F-actin filaments and tubulin, were aligned perpendicular to the stretch force vector. Tyrosine-phosphorylated molecules which are localized in focal adhesion plaques and MAP kinase might be related to signal transduction caused by mechanical stress.
2.When peripheral blood leukocytes/monocytes were cultured with M-CSF,the number of osteoclast like cells, which were multinuclear, lamellipodia-positive and TRAP-positive cells increased. When these cells were cultured on slices of bovine dental root, pit formations were observed. Macrophages of PBL proliferate by blastogenesis and a part of the blastgenic macrophages differentiate to osteoclasts by M-CSF and 1,25 (OH) _2D_3. Moreover the number of osteoclast-like cells shown in PBL
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treated in M-CSF or GM-CSF was suppressed by coculture fluid of PBL/PDL cells.
3.Mechanical stress of tooth movement differently affected the alveolar bone and cellular cementum ; the bone was resorbed whereas the cementum resisted resorption and its calcification is inhibited under the compressive force of tooth movement. The expression of CH-6S is related to the compressive force in non-hyalinized and hyalinized PDL,whereas that of CH-4S/DS is not influenced by the mechanical stress. Osteocalcin expression of cementblasts forming acellular cementum is similar to that of cells forming cellular cementum as well as osteoblasts and odontblasts, and has a role for calcification of acellular cementum. Topical administration of a bisphosphonate (Risedronate) inhibits orthodontic tooth movement and root resorption.
4.Localization and distribution of the ECMs ; Type I,II,III,X collagen, osteocalcin and GAGs were analyzed, using immunohistochemical techniques. The marked regional differences cxit in the phenotypic expression of ECMs in tissues, may reflect the local functional environment and cellular response. Less
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