Kaji H, Sugimoto T, Kanatani M, Fukase M, Kumegawa M, Chihara K
Department of Medicine, Kobe University School of Medicine, Japan.
Life Sci. 1995;56(22):1903-13. doi: 10.1016/0024-3205(95)00165-3.
Although retinoic acid (RA) has been considered to be a bone-resorbing agent both in vivo and in vitro, its mechanism remains still unclear. The present study was performed to examine the effect of RA on osteoclast-like cell formation in the presence or absence of osteoblasts and to study whether RA would affect osteopontin mRNA expression in isolated rabbit osteoclasts. RA (10(-8) and 10(-6) M) significantly stimulated the formation of osteoclast-like cell in osteoblast-containing mouse bone cell cultures. Also, RA caused a stimulation of osteoclast-like cell formation from hemopoietic blast cells supported by granulocyte macrophage-colony stimulating factor (GM-CSF) in mouse spleen cell cultures. However, RA did not affect blast cell number in these cultures and significantly inhibited GM-CSF-stimulated proliferation of hemopoietic blast cells. On the other hand, RA stimulated the bone-resorbing activity of mature osteoclasts in mouse bone cell cultures. Moreover, RA caused a stimulation of osteopontin mRNA expression in isolated rabbit osteoclasts. The present study demonstrated for the first time that RA stimulated osteoclast-like cell formation, presumably through directly acting on the hemopoietic blast cells, and that RA stimulated osteopontin mRNA expression in isolated rabbit osteoclasts.
尽管视黄酸（RA）在体内和体外均被认为是一种骨吸收剂，但其机制仍不清楚。本研究旨在检测在有或无成骨细胞存在的情况下RA对破骨细胞样细胞形成的影响，并研究RA是否会影响分离的兔破骨细胞中骨桥蛋白mRNA的表达。RA（10^(-8)和10^(-6) M）显著刺激含成骨细胞的小鼠骨细胞培养物中破骨细胞样细胞的形成。此外，在小鼠脾细胞培养物中，RA可刺激由粒细胞巨噬细胞集落刺激因子（GM-CSF）支持的造血母细胞形成破骨细胞样细胞。然而，RA并不影响这些培养物中母细胞的数量，且显著抑制GM-CSF刺激的造血母细胞增殖。另一方面，RA可刺激小鼠骨细胞培养物中成熟破骨细胞的骨吸收活性。此外，RA可刺激分离的兔破骨细胞中骨桥蛋白mRNA的表达。本研究首次证明，RA可能通过直接作用于造血母细胞刺激破骨细胞样细胞的形成，并且RA可刺激分离的兔破骨细胞中骨桥蛋白mRNA的表达。
