| Co-Investigator(Kenkyū-buntansha) |
DEGUCHI Toru Medical and dental hospital, Senior assistant professor, 医学部・歯学部附属病院, 講師 (30346457)
FUKUNAGA Tomohiro Kagoshima-University, Medical and dental hospital, Senior assistant professor, 医学部・歯学部附属病院, 講師 (70362994)
SUGAWARA Yasuyo Graduate school of medicine, Dentistry and pharmaceutical sciences, Assistant professor, 大学院医歯薬学総合研究科, 助手 (70379775)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2005: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Research Abstract |
We evaluated the factors associated to odontclast expression, proliferation, differentiation and inhibition during experimental tooth movement. Using six-week-old male ICR mice, the upper right first molars were palatally moved with 0.012-inch super elastic nickel-titanium wire which was attached on their incisors with composite resin. One, 2, 3, 5, 7, and 14 days after the starting of tooth movement, animals were anesthetized and perfused with 4% paraformaldehyde. The maxillary bones and surrounding tissues were dissected and fixed in the above solution for approximately 24 hours at 4C. The specimens, decalcified in 20% ethylenediaminetetraacetate for 14 days at 4°C, were dehydrated and embedded in paraffin. The tissue blocks were cut into serial sections 5 pμm thick. We determined the multi-nuclear cells stained with tartrate-resistant acid phosphate (TRAP) as odontoclasts and observed them using the microscopy. In situ hybridization using RNA probe of Connective tissue growth factor (CTGF), Cbfal, Osteopontin(OPN), Osteocalcin (OSC), Type I Collagen, was performed on these specimens, and we observed time course changes of these factors. In addition, immunohistochemistry was also performed to reveal the expression of their proteins.
Five day and 7 days after the start of the tooth movement, significant expression of odontoclasts were observed around the teeth. After 5 and 7 days, odontoclasts expressing OPN mRNA and CTGF were observed on not only the compression side but also the tension side. The odontoclasts were positive for TRAP staining and did not express osteocalcin mRNA. The present findings suggested that OPN and CTGF might play an important role in root resorption the same as those in bone resorption during experimental tooth movement. Then, we synthesized plasmid DNA including the genes of β-galactosidase [LacZ], OPN and CTGF and HVJ-liposome complex, and introduced them around the upper first molar before the experimental tooth movement.
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