Arnett T R, Dempster D W
Endocrinology. 1987 Feb;120(2):602-8. doi: 10.1210/endo-120-2-602.
Disaggregated chick osteoclasts sedimented onto bovine cortical bone slices excavate deep and sharply defined resorption lacunae that stain intensely with toluidine blue. We have used this observation to develop a simple light microscopic method for quantifying the bone resorptive activity of chick osteoclasts in vitro. Using this technique, we have found that disaggregated chick osteoclasts are strikingly less sensitive than rat osteoclasts to salmon calcitonin (sCT). Bone resorption by rat osteoclasts was completely abolished by synthetic sCT at a concentration of 10 pg/ml. In contrast, sCT at concentrations up to 100 micrograms/ml did not significantly inhibit bone resorption by chick osteoclasts. Bone resorption by chick osteoclasts could, however, be inhibited by prostaglandin E2 at concentrations of 10(-6) M or more. In time-lapse video experiments, the motility of rat osteoclasts was rapidly inhibited by sCT (5-50 pg/ml), prostaglandins I2 and E2 (less than or equal to 10(-4) M), and Bu2cAMP (2.5 X 10(-4) M), whereas chick osteoclasts failed to show such a response. These findings suggest that CT does not play an important role in the regulation of osteoclastic activity in the chick and may explain why injection of the hormone has generally not been found to evoke an acute hypocalcemic response in birds. This fundamental difference in response to CT may limit the utility of chick osteoclast systems as models of mammalian bone resorption.
沉积在牛皮质骨切片上的分散鸡破骨细胞会挖掘出深且边界清晰的吸收陷窝，这些陷窝用甲苯胺蓝染色时颜色很深。我们利用这一观察结果开发了一种简单的光学显微镜方法，用于体外定量鸡破骨细胞的骨吸收活性。使用该技术，我们发现分散的鸡破骨细胞对鲑鱼降钙素（sCT）的敏感性明显低于大鼠破骨细胞。浓度为10 pg/ml的合成sCT可完全消除大鼠破骨细胞的骨吸收。相比之下，浓度高达100微克/毫升的sCT对鸡破骨细胞的骨吸收没有显著抑制作用。然而，浓度为10^(-6) M或更高的前列腺素E2可抑制鸡破骨细胞的骨吸收。在延时视频实验中，sCT（5 - 50 pg/ml）、前列腺素I2和E2（小于或等于10^(-4) M）以及Bu2cAMP（2.5×10^(-4) M）可迅速抑制大鼠破骨细胞的运动，而鸡破骨细胞未表现出这种反应。这些发现表明，CT在鸡破骨细胞活性调节中不起重要作用，这可能解释了为什么一般未发现注射该激素会在鸟类中引发急性低钙血症反应。这种对CT反应的根本差异可能会限制鸡破骨细胞系统作为哺乳动物骨吸收模型的实用性。
