The mechanism of cell locomotion of cultured osteoclasts in three-dimensions ; the observation by time-cinematography

分离ddy系小鼠的破骨细胞和巨噬细胞，然后与或不与牙本质切片一起培养72小时。孵育后，用偶氮染料法检测抗酒石酸酸性磷酸酶（TRACPase）和二价磷酸酶（ACT3）的活性。ACPasc阳性细胞吞噬印度墨汁，但它们既不显示TRACPase也不显示反应活性。TRACP酶阳性细胞在牙本质切片上形成陷窝，边缘皱褶，透明带。因此，具有吞噬作用的ACP酶阳性细胞似乎是巨噬细胞，而TRACP酶阳性细胞是破骨细胞。光镜下在牙本质切片上观察到一个多核的TRACP酶阳性细胞，其轮廓复杂，然后将该细胞用半薄切片和普通切片交替连续切片，观察其超微结构和三维结构。透射电镜观察，该细胞与破骨细胞的结构相似，具有清晰的带状结构，但无皱褶边界。三维重建显示该细胞外形扁平复杂，胞体向牙本质切片背面延伸。这些结果表明，该细胞可能是一种增殖性破骨细胞。

Osteoclasts and macrophages of ddy strain mice were isolated, and then culturedwith or without dentine slices for 72 hours. After the incubation, tartrate-resistant acid phosphatase (TRACPase) and adic phosphateas (ACPase) activities were detected in them by the azo dye method. ACPasc-positive cells phagocytized indian inks, however, they showed neither TRACPase nor resosrptive activity. TRACPase-positive cells made lacunae on the dentine slices, and showed sthe ruffled border and clear zone. Therefore, ACPase-positive cells with phagocytosis were seemed to be macrophages, and TRACPase-positive cells were osteoclasts. These results suggested that TRACPase activity was specific for osteoclastic cells, not macrophages, in 72 hours culture of ddy mice.One multinucleated TRACPase-positive cell with comnplicated contours was observed on the dentine slice by light microscopy, and then this cell was serially sectioned by altermating semithin and ultrathin sections to observe its ultrastructure and three-dimensional sturcture. By transmission electron microscopy, this cell had the similar structure as those of osteoclasts, and possessed the clear zone-like structures, but showed no ruffled border. A three-dimensional reconstruction showed that this cell had very flat and complicated outlines, and extended its cell body to the back side of the dentine slice. These results suggested that this cell might be a locomoting osteoclast.