2005 Fiscal Year Final Research Report Summary
Involvement of neurotrophins in development/regeneration of the periodontal Ruffini endings-An analysis using NT-4/5 KO mice
| Project/Area Number |
16390522
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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 |
Morphological basic dentistry
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| Research Institution | Niigata University |
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Principal Investigator |
MAEDA Takeyasu Niigata University, Institute of Medicine and Dentistry, Professor, 医歯学系, 教授 (40183941)
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| Co-Investigator(Kenkyū-buntansha) |
AMIZUKA Norio Niigata University, Center for Transdisciprinary Research, Professor, 超域研究機構, 教授 (30242431)
KAWANO Yoshiro Niigata University, Institute of Medicine and Dentistry, Assistant, 医歯学系, 助手 (60303129)
INOUE Kayoko (NOZAWA Kayoko) Niigata University, Institute of Medicine and Dentistry, Assistant, 医歯学系, 助手 (90303130)
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| Project Period (FY) |
2004 – 2005
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| Keywords | neurotrophin / neurotrophin receptor / periodontal Ruffini ending / development / regeneration / NT-4 / 5 / transgenic mouse / immunocytochemisty |
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| Research Abstract |
Our previous studies have shown the involvement of brain derived neurotrophic factor (BDNF) in the development and regeneration of the periodontal Ruffini endings. Since TrkB, a ligand for BDNF, also binds NT-4/5, the present research project was undertaken to investigate the development and regeneration of the periodontal Ruffini ending in the NT-4/5 homozygous mice, compared to wild-type mice by immunocytochemistry and quantitative analysis. The obtained main results are as follows.
1.Developmental aspects of terminal morphology and chronological changes in neural density
The quantitative analysis showed that the neural density of the periodontal nerve fibers increased day by day to reach a plateau at postnatal 8 weeks both typed mice. Compared to wild type mice, the homozygous mice exhibited lower neural density with significant differences by postnatal weeks 8 (PO 8w). In addition, there were significant differences between PO2 and 3w, and PO3 and 8w in the homozygous mice
2.Protein and mRNA levels for TrkB and p75-NGFR did not differ in the trigeminal ganglion and periodontal ligament between wild type and homozygous mice.
3.No significant difference in morphology and density of the terminal Schwann cells was found between wild type and homozygous mice.
4.In an experimental study to injury inferior alveolar nerve, the regeneration of the periodontal Ruffini endings delayed in the homozygous mice during the observation period. In particular, the homozygous mice showed apparent lower neural density through PO3 and 10 days.
These findings strongly suggest that NT-4/5 plays in crucial roles in development and regeneration at early stage. Combined with our previous studies on BDNF-KO mice, the development and regeneration of the periodontal Ruffini endings are controlled by multiple neurotrophins in a time dependent manner.
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