Zaman G, Dallas S L, Lanyon L E
Department of Veterinary Basic Sciences, Royal Veterinary College, London, UK.
Calcif Tissue Int. 1992 Aug;51(2):132-6. doi: 10.1007/BF00298501.
Pairs of 17-day embryonic chick tibiotarsi were removed and maintained in organ culture. One of each pair was subjected to a single 20-minute period of intermittent loading at 0.4 Hz, producing peak longitudinal compressive strains of 650 microstrain (mu epsilon). In the 18-hour culture period following loading, alkaline phosphatase levels in the osteoblasts of the loaded tibiotarsi were maintained whereas in controls they declined. In situ hybridization using a collagen type I cRNA riboprobe showed a substantial increase in expression of mRNA for collagen type I in the periosteal tissue of bones that were cultured for 18 hours after loading compared with that in similarly cultured controls and bones cultured for 4 hours. These results demonstrate that appropriate loading of embryonic chick bones in organ culture elicits adaptive regulation of matrix synthesis as evidenced by increased expression of the gene for type I collagen and alkaline phosphatase activity. This model may be useful as it must contain all the obligatory steps between strain change in the matrix and modified osteogenic activity.
取出17日龄鸡胚的成对胫跗骨并进行器官培养。每对中的一根骨接受在0.4Hz下单次20分钟的间歇性加载，产生650微应变（με）的峰值纵向压缩应变。在加载后的18小时培养期内，加载的胫跗骨成骨细胞中的碱性磷酸酶水平保持不变，而对照中的碱性磷酸酶水平下降。使用I型胶原cRNA核糖探针进行原位杂交显示，与同样培养的对照和培养4小时的骨相比，加载后培养18小时的骨的骨膜组织中I型胶原mRNA的表达显著增加。这些结果表明，在器官培养中对鸡胚骨进行适当加载可引发基质合成的适应性调节，这可通过I型胶原基因表达增加和碱性磷酸酶活性得到证明。该模型可能有用，因为它必须包含基质应变变化与成骨活性改变之间的所有必要步骤。
