若年齢および成熟マウスにおける高気圧酸素療法が骨再生へ及ぼす影響について

内容の要約広島大学(Hiroshima University)博士(歯学)Doctor of Philosophy in Dental Sciencedoctora

Effects of loxoprofen on the apical root resorption during orthodontic tooth movement in rats.

Studies have revealed that severe apical root resorption during tooth movement is caused by the noninfective inflammatory reaction of apical root tissues. We hypothesized that loxoprofen can suppress apical root resorption during tooth movement. Cyclic tensile force (CTF) of 10 kPa was applied to the human pulp cells for 48 hours by the Flexcell Strain Unit. Loxoprofen (10 and 100 μM) was added to the culture cells, and expression of cyclooxygenase (COX)-1, COX-2, interleukin (IL)-1β, receptor activator of nuclear factor kappa-B ligand (RANKL), tumor necrosis factor (TNF)-α, and macrophage colony-stimulating factor (M-CSF) were examined. To determine the effects of loxoprofen sodium on apical root reabsorption during tooth movement, the upper first molars of 7-week-old rats were subjected to mesial movement by 10g force for 30 days with or without the oral administration of loxoprofen. Gene expression and protein concentration of COX-1, COX-2, IL-1β, TNF-α, RANKL and M-CSF were significantly higher in the CTF group than in the control group. However, these levels were decreased by loxoprofen administration. After orthodontic tooth movement, the expression of IL-1β, TNF-α, RANKL and M-CSF decreased in the loxoprofen group than in the control group by immunohistochemical staining. In comparison to control group, less number of odontoclasts and a decrease in the amount of apical root resorption was observed in the loxoprofen group. Many osteoclasts became visible on the pressure side of the alveolar bone in the both groups, and the amount of tooth movement did not show a significant difference. These findings demonstrate that severe apical root resorption may be suppressed by loxoprofen administration, without a disturbance of tooth movement

The amount of root resorption.

<p>The amount of root resorption was significantly greater in the control group (tooth movement without drug) than in the loxoprofen group (tooth movement with loxoprofen) (**P< 0.01, N = 5).</p

Immunohistochemical staining for RANKL.

<p>(A) non-tooth movement without drug (B) tooth movement without drug (C) tooth movement with loxoprofen.</p

Observation of bone and root resorption area.

<p>The number of osteoclasts, odontoclasts and the amount of root resorption were examined at square area (1200 × 1200 μm²) in root apex.</p

CTF application and addition of loxoprofen sodium.

<p>A maximal cell lengthening of 20% is created by a stain unit (FX-2000) with or without loxoprofen sodium.</p

The effects of loxoprofen sodium on the expression of COX-1, COX-2, IL-1β, TNF-α, RANKL and M-CSF mRNA in pulp cells stimulated by a 10-kPa tensile force for 48 hours.

<p>(A) Dotted line indicates the expression of COX-1, (B) COX-2, (C) IL-1β, (D) TNF-α, (E) RANKL, and (F) M-CSF mRNAs in the control group. COX-1, IL-1β, RANKL, and M-CSF mRNA levels were decreased significantly in the 10- and 100-μM loxoprofen groups. COX-2, TNF-α mRNA level was decreased significantly in the 100-μM loxoprofen group compared with the CTF group (*P< 0.05, **P< 0.01, N = 4).</p