| Project/Area Number |
11470402
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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 |
Conservative dentistry
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| Research Institution | NIIGATA UNIVERSITY (2001)
Tokyo Medical and Dental University (1999-2000) |
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Principal Investigator |
OKIJI Takashi NIIGATA UNIVERSITY, DENTAL HOSPITAL, PROFESSOR, 歯学部・附属病院, 教授 (80204098)
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| Co-Investigator(Kenkyū-buntansha) |
KAWASHIMA Nobuyuki NIIGATA UNIVERSITY, GRADUATE SCHOOL, TOKYO MEDICAL & DENTAL UNIVERSITY, ASSISTANT, 大学院・医歯学総合研究科, 助手 (60272605)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥15,400,000 (Direct Cost: ¥15,400,000)
Fiscal Year 2001: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2000: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1999: ¥11,000,000 (Direct Cost: ¥11,000,000)
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| Keywords | dendritic cell / macrophage / HLA-DR / inflammatory cytokines / inducible nitric oxide synthase / cvclooxvgenase-2 / dental caries / pulpitis / 歯髄 / 共刺激分子 / 免疫組織化学 / 分子生物学 / サイトカイン / inducible nitric oxide synthase / RT-PCR |
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| Research Abstract |
Immunohistochemical and molecular biological analyzes were conducted in order to investigate the roles of pulpal densritic cells (DCs) in the pathogenesis of pulpal diseases. Results obtained were as follows:
1. In human teeth bearing pulp exposure-free dentinal caries, HLA-DR-expressing pulpal DCs exhibited a localized accumulation beneath the affected dentinal tubules. The accumulation was evident in teeth with a shallow carious lesion. The majority of'the pulpal DCs expressed CD14 and CD68. In teeth with a deep carious lesion, expression of CD83 and CD86 was detected on some DCs. T cells showed a marked increase in teeth with shallow dentinal caries. These T cells were mostly memory cells expressing CD45RO, and some of them co-expressed CD25, a marker for activated T cells. However, B cells showed an increase only in teeth with deep dentinal caries. These results suggest that DC-T cell interaction and subsequent activation of T cells are involved in the initial pathogenesis of pulpal diseases.
2. Expression of inducible nitric oxide synthase (iNOS) mRNA in LPS-induced pulpitis of rat upper incisors peaked at 6 hrs, which was detected by means of reverse transcription polymerase chain reaction (RT-PCR). Immunohistochemical staining for rat iNOS revealed that most of the iNOS-positive cells were macrophages. The expression of mRNAs for cyclooxygenase-2 (COX-2) and pro-inflammatory cytokines peaked at 3 to 6 hrs, whereas IL-10 (anti-inflammatory cytokine) mRNA was first detected at 6 hrs. Administration of an iNOS inhibitor caused drastic decrease in the expression of mRNAs for COX-2 and inflammatory cytokines in the inflamed pulp. These results indicate that NO generated by macrophages may regulate the pulpal inflammatory reactions.
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