Lee K L, Aubin J E, Heersche J N
MRC Group in Periodontal Physiology, Faculty of Dentistry, University of Toronto, Ontario, Canada.
J Bone Miner Res. 1992 Oct;7(10):1211-9. doi: 10.1002/jbmr.5650071013.
When fetal rat calvarial cells are cultured in medium containing vitamin C, osteoid nodules develop after approximately 15 days of culture. Upon addition of an organic phosphate (beta-glycerophosphate, beta GP), these nodules mineralize. We have now used this system to explore the suggestion made by others that a negative feedback may exist between matrix mineralization on the one hand and the synthesis of alkaline phosphatase and bone matrix collagen on the other by analyzing the synthesis of these proteins and the levels of their mRNAs in mineralizing and nonmineralizing cultures. Our results indicate that in the osteoid nodule-bone nodule system, matrix mineralization did not affect the mRNA levels for osteopontin, type I collagen, bone sialoprotein, or osteocalcin. Synthesis of total protein and collagen and the osteocalcin content of culture media were also not different in the mineralizing and nonmineralizing cultures. However, alkaline phosphatase mRNA was increased in early mineralizing cultures and alkaline phosphatase activity in the cell layer was also increased in mineralizing cultures. Thus, the hypothesis that a direct negative feedback exists between mineralization and matrix protein synthesis is not supported by our experiments.
当将胎鼠颅骨细胞培养于含维生素C的培养基中时，培养约15天后会形成类骨质结节。加入有机磷酸盐（β-甘油磷酸酯，β GP）后，这些结节会矿化。我们现在利用这个系统来探究其他人提出的一种观点，即通过分析这些蛋白质的合成及其mRNA在矿化和非矿化培养物中的水平，在一方面的基质矿化与另一方面的碱性磷酸酶和骨基质胶原的合成之间可能存在负反馈。我们的结果表明，在类骨质结节-骨结节系统中，基质矿化并不影响骨桥蛋白、I型胶原、骨唾液蛋白或骨钙素的mRNA水平。矿化和非矿化培养物中总蛋白和胶原的合成以及培养基中的骨钙素含量也没有差异。然而，在早期矿化培养物中碱性磷酸酶mRNA增加，并且在矿化培养物中细胞层中的碱性磷酸酶活性也增加。因此，我们的实验不支持矿化与基质蛋白合成之间存在直接负反馈的假说。
