Benkhaial G S, Cheng K M, Shah R M
Department of Oral Biology, University of British Columbia, Vancouver, Canada.
J Craniofac Genet Dev Biol. 1993 Jan-Mar;13(1):6-17.
A study was undertaken to examine the involvement of collagen synthesis during palate development in quail where mammalian-type shelf reorientation is absent. Teratological observation showed that 100 micrograms 5-fluorouracil (FU) on day 4 of incubation increased the gap between the palatal shelves. Light microscopic observation indicated that the quail palatal shelves develop as horizontal ridges on day 5 and approximate on day 8 of incubation but never fuse. FU treatment affected the approximation of palatal shelves. In separate experiments, both the control and FU-treated quail embryonic palates, which were dissected between days 5 and 10 of incubation, were incubated in a growth medium supplemented with 14C-proline. The rate of collagen synthesis, total protein, hydroxyproline (HYP) levels, and collagen isotype were determined. The result showed that in control palates the rate of collagen synthesis increased fivefold between days 6 and 8 of incubation but dropped thereafter. In FU-exposed palates, the rate of collagen synthesis was lower than that in controls. It increased threefold between days 7 and 8 of incubation. High performance liquid chromatographic measurement of HYP levels indicated that, in comparison to controls, HYP accumulation in FU-treated palates was reduced by 50% on day 6 and 75% on day 8 of incubation. Total protein content in FU-treated palate were also 50-70% lower than those in their control counterparts between days 5 and 10 of incubation. Gel electrophoresis showed that only type I collagen was synthesized in the developing palate of both the control and FU-treated quail embryo. An analysis of results of the present study, along with the data from literature on mammals, corroborate the proposition that an increased collagen synthesis may contribute to the acquisition of volume of vertebrate's secondary palatal shelf for its continuing morphogenesis.
进行了一项研究，以检查在鹌鹑腭发育过程中胶原合成的参与情况，鹌鹑不存在哺乳动物型腭突重新定向。致畸学观察表明，孵化第4天注射100微克5-氟尿嘧啶（FU）会增加腭突之间的间隙。光学显微镜观察表明，鹌鹑腭突在孵化第5天发育为水平嵴，在孵化第8天接近但从未融合。FU处理影响了腭突的接近。在单独的实验中，将在孵化第5至10天之间解剖的对照和FU处理的鹌鹑胚胎腭在补充有14C-脯氨酸的生长培养基中培养。测定胶原合成速率、总蛋白、羟脯氨酸（HYP）水平和胶原同型。结果表明，在对照腭中，胶原合成速率在孵化第6至8天增加了五倍，但此后下降。在暴露于FU的腭中，胶原合成速率低于对照。它在孵化第7至8天增加了三倍。HYP水平的高效液相色谱测量表明，与对照相比，在孵化第6天，FU处理的腭中HYP积累减少了50%，在孵化第8天减少了75%。在孵化第5至10天之间，FU处理的腭中的总蛋白含量也比其对照对应物低50-70%。凝胶电泳显示，对照和FU处理的鹌鹑胚胎发育中的腭中仅合成I型胶原。对本研究结果的分析以及来自哺乳动物文献的数据证实了这一观点，即胶原合成增加可能有助于脊椎动物次生腭突获取体积以进行持续的形态发生。
