2000 Fiscal Year Final Research Report Summary
Reaction of intercellular network of osteocytes in alveolar bone during experimental tooth movement
| Project/Area Number |
10470449
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
矯正・小児・社会系歯学
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| Research Institution | Health Sciences University of Hokkaido |
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Principal Investigator |
MIZOGUCHI Itaru Dentistry, Health Sciences University of Hokkaido, Professor, 歯学部, 教授 (20200032)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAKURA Yasunori Dentistry, Health Sciences University of Hokkaido, Associate professor, 歯学部, 助教授 (60128915)
KAGAYAMA Manabu Dentistry, Tohoku University Professor, 歯学部, 教授 (60004610)
YAJIMA Toshihiko Dentistry, Health Sciences University of Hokkaido, Professor, 歯学部, 教授 (10018749)
SASANO Yasuyuki Dentistry, Tohoku University Assistant, 歯学部, 助手 (30196191)
TAKEUCHI Makoto Dentistry, Health Sciences University of Hokkaido, Instructor, 歯学部, 講師 (00143595)
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| Project Period (FY) |
1998 – 2000
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| Keywords | tooth movement / osteocyte / cell death / Apoptosis / necrosis |
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| Research Abstract |
Osteocytes are buried within the bone matrix and form complicated cellular networks between neighboring osteocytes and/or osteoblasts on bone surfaces. It is proposed that osteocytes have very important role of bone remodeling. However little is known on the effect of mechanical stress on osteocytes and their intercellular network in the alveolar bone during orthodontic tooth movement. The purpose of this study was to examine the intercellular network in alveolar bone on pressure and tension sides during experimental tooth movement, using morphometrical analysis, immunohistochemistry and in situ hybridization technique.
1. Animals and experimental tooth movement.
In 8-week-old male Wistar rats, the upper first molar was forced to move mesially with an average load of 10g by a nickel-titanium superelastic wire (0.01 inch in diam.). We previously reported that the method was suitable for the observation of osteocytes adjacent to the hyalinized periodontal tissue.
2. Morphological change of osteocytes during experimental tooth movement.
We developed a method to observe osteocytes by immunofluoresence with Alexa 488 labelled phalloidin and DAPI under confocal laser scanning microscopy (CLSM). CLSM showed that chromatin condensation, nuclear fragmentation and cytoplasmic destruction appeared in several osteocytes adjacent to the hyalinized periodontal tissues. Also, we carried out TUNEL method and electronmicroscopic observation to identify the cell death of osteocytes. The results indicate that cell death of osteocytes during experimental tooth movement may be due to disruption of intercellular network between osteoblasts and osteocyte, but not to direct reaction of osteocytes by mechanical stress. To know the dynamics of intercellular network in alveolar bone, further investigations concerning involvement of several growth factors and cytokines related to bone metabolism is necessary.
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