| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2004: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
In our previous study, we demonstrated that the molecular weights of hyaluronic acid (HA) in synovial fluid from temporomandibular joint (TMJ) samples from patients with internal derangement and osteoarthritis are decrease. In this study, we hypothesized that the decreased in molecular weights of HA could affect on the degradation of TMJ. Then we examined the effects of HA at several molecular weights on osteoclast formation and function induced by RANKL (receptor activator of NF-kB ligand) in a mouse monocyte cell line (RAW 264.7). HA at Mr<8,000 (low molecular weight HA (LMW-HA)) enhanced tartrate-resistant acid phosphatase-resistant acid phosphatase activity induced by RANKL in a dose-dependent manner, whereas HA at Mr > 900,000 (high molecular weight (HMW-HA)) showed no effect on osteoclast differentiation. LMW-HA enhanced pit formation induced by RAW 264.7 cells, whereas HMW-HA did not, and LMW-HA stimulated the expression of RANK (receptor activator of NF-kB) protein in RAW 264.7 cells. In addition, we found that LMW-HA enhanced the levels of c-Src protein and phosphorylation of ERKs, whereas the p38 MAPK inhibitor inhibited RANKL-induced osteoclast differentiation. These data suggests LMW-HA plays a important role in osteoclast differentiation and function in temporomandibular disorders, in which molecular weight of HA is decreased.
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