| Project/Area Number |
02670929
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
小児・社会系歯学
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| Research Institution | Showa University |
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Principal Investigator |
SHIBATA Yasunori Showa Univ., Instructor, 歯学部, 講師 (50138400)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Shigeru Showa Univ., Assistant, 歯学部, 助手 (20195986)
HIRAIDE Takatoshi Showa Univ., Assistant Prof., 歯学部, 助教授 (80129866)
SHIBASAKI Yoshinobu Showa Univ., Prof., 歯学部, 教授 (40014005)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1990: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | PDL cell / Bone cell / DNA / ALP / Mechanical stretch / Intermittent stress / Collagen gel / Embedded culture / 細胞培養 / Prostaglandin E / 骨吸収活性 / Interleukinー1 / Indomethachin / Conditioned medium |
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| Research Abstract |
Human Periodontal ligament(PDL)cells derived from healthy premolars extracted for orthodontic treatment were utilized for in vitro experiments in passage 4-6. Bone cells derived from neonatal rat calvariae were also used for study in the second passage. Human PDL cells or rat bone cells embedded in type I collagen were seed into the culture units made of nylon mesh. After 24h of preincubation, bone cells were incubated for 48h and PDL cells were incubated for 24h, 48h or 72h with or without intermittent mechanical stretch(active for 15min, resting for 45min)in the mechanical cell stimulator placed in CO_2 incubator. After incubation. the stretched or the unstretched cells were prepared for measurement of DNA and alkaline phosphatase(ALP)activity, and f or the histological observation. The cultured cells embedded in collagen gel matrix were three dimensionaly stretched and the amount of the stretch varied from 10% to 20%. Significant DNA increase was observed for both PDL cells and bone
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cells, when the cells were stretched only for 48h of incubation. However, the optimal amplitude of the stretch was different depending on each particular cell types(PDL cells = 15 %, bone cells = 10 %). ALP activity was measured only for bone cells and the data indicated that optimal amplitude(10 %)for enhancing DNA synthesis had inhibitory effect for ALP activity. These data indicated that intermittent mechanical stretch seems to be one of the factors which enhance cell proliferation and inhibit cell differentiation. In the case of PDL cells, another experiment was performed for DNA synthesis in the presense of PGE_2(10^<-6>M). The effect of exogenous administration of PGE_2 for stimulating DNA synthesis was almost equivalent or even more than that of mechanical stretch(15 %). Moreover, additive effect was observed for DNA synthesis when combined. These findings suggested that the mechanisms of these two factors(chemical and mechanical stress)are fundamentally different. The histological changes were also observed for PDL cells and bone cells for 48h with intermittent mechanical stretch. In this culture system, PDL cells and bone cells with certain amount of mechanical stretch could keep the physiological and three dimensional conditions that is presumably analogous in some degree to the cells in vivo. Less
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