An Experimental Study on the Effect of Cytoskeletal Changes or Osteoblastic Cell Activities

골모세포유사세포의 cytoskeletal change가 세포 활성에 미치는 영향에 관한 실험적 연구

The cytoskeleton has been shown to form a network, connecting the extracelluar matrix via integrin with the nucleus and the cytoplasmic constituents of the cell. It is therefore assumed that the cytoskeleton may mediate signals generated by perturbations originating in the matrix. The purpose of this study is to examine the effect of cytoskeletal change on osteoblastic cell activities. The author cultured osteoblastic cells obtained from neonatal mouse calvaria. The cells were teated with cytochalasin B(CB) or colchicine (COL) at four concentrations for 3 hours and after another 24 hours the conditioned media was collected and assayed for prostaglandin $E_2\;(PGE_2)$, interleukin-6(IL-6), tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and matrix metalloproteinase-1(MMP-1). In addition, the cytoskeletal protein actin were observed by immuno-fluorescence. The results were as follows: 1. The production of $PGE_2$ showed the tendency to be increased in CB-treated group. $PGE_2$ was increased in COL-treated group dose-dependantly, 2. IL-6 production, in CB-treated group, was increased, except at 1.0 ${\mu}g/ml$. IL-6 was induced in COL-treated group. 3. TNF-$\alpha$ production was increased in CB-treated group, except at 1.0 ${\mu}g/ml$, and in COL-treated group, that was increased. 4. The MMP-1 production was decreased in CB-treated soup and was not changed in COL-treated group, which could be selectively visualized by immunoblotting with monospecific antibody. 5. The cytoskeletal actin stress fibers were disappeared and the cells showed to be rounded in CB-treated group. These results indicated that there are a relationship between the cytoskeletal rearrangements and osteoblastic cell activities, especially in release of paracrine/autocrine factors, such as $PGE_2$, IL-6, and TNF-$\alpha$.

Cytoskeleton은 세포핵과 세포외 기질을 연결하고 있어서 기질에 가해지는 물리적 힘에 의해 cytoskeletal change가 유도되고 이에 의해 세포의 개조활성이 영향을 받는다고 생각되어 왔다. 본 연구는 골모세포 활성에 대한cytoskeletal change의 역할을 규명하기 위한 것으로서, 신생 백서로부터 조골세포양 세포를 분리, 배양하고 네가지 농도의 cytochalasin B(CB) 또는 colchicine(COL)을 3시간 처리하였다. 다시 배양액을 교환하고 24시간 동안 배양하여 prostaglandin $E_2\;(PGE_2)$, interleukin-6(IL-6), tumor necrosis factor-$\alpha$(TNF-$\alpha$) 및 matrix metalloproteinase-1 (MMP-1) 생산을 측정하고 통계적으로 비교하였으며 cytoskeletal protein actin 변화를 관찰하기위하여 면역형광염색하고 형광현미경으로 관찰하여 다음과 같은 결과를 얻었다: 1. CB 처리군에서 $PGE_2$ 생산이 증가되는 경향을 보였고 COL 처리군에서는 약물농도에 비례하여 증가하였다. 2. IL-6 생산은 CB농도 1.0 ${\mu}g/ml$일때를 제외하고 증가되었다. 3. TNF-$\alpha$도 CB 농도가 1.0 ${\mu}g/ml$ 일때를 제외하고 증가하였다. 4. MMP-1 생산은 CB 처리군에서 감소하는 경향을 보이고 COL 처리군에서는 변화되지 않았다. 5. CB처리군에서는 cytoskeletal actin stress fibers가 사라지고 세포모양이 둥글어지는 경향을 보였다. 이상의 결과로 미루어 보아 cytoskeletal rearrangement는 골모세포유사세포의 활성, 특히 $PGE_2$, IL-6, 및 TNF-$\alpha$같은 paracrine/autocrine factor의 생산과 관련있는 것으로 보인다.