Mansell J P, Kerrigan J, McGill J, Bailey J, TeKoppele J, Sandy J R
Division of Child Dental Health, University of Bristol Dental School, Lower Maudlin Street, BS1 2LY, Bristol, UK.
Mech Ageing Dev. 2000 Oct 20;119(1-2):49-62. doi: 10.1016/s0047-6374(00)00168-8.
Cleft lip and palate is a common craniofacial malformation in man. The aetiology is multifactorial and not known. Since collagen is a major structural component of the developing palate, we studied its composition and metabolism during palate shelf formation and elevation in the rat. Palatal shelves were harvested at embryonic days (E) 15, 16 and 17 as well as post-partum. Palatal collagen increased threefold from E15 to E17 and tenfold from E17 to 5-day-old pups. Palatal calcification was seen in the main, post-partum. Collagen cross-linking, which may be important in shelf elevation and union, varied. The concentration of hydroxylysyl-pyridinolone cross-links was greatest prior to shelf elevation, declining thereafter. Similarly, the highest concentration of dihydroxylysinononorleucine was seen at E16 and this supports the concept of a compliant mesenchymal shelf responding to an intrinsic elevating force. We then determined if enzymes responsible for matrix degradation, matrix metalloproteinases (MMP) and the tissue inhibitors of metalloproteinases (TIMPs) altered over the same time periods. MMP-2, and TIMP-1 and TIMP-2 were identified by gelatin zymography and reverse zymography, respectively. MMP-3 activity was determined with a fluorogenic substrate assay. TIMP-1, TIMP-2 and MMP-3 levels remained constant from E15 to E17. The MMP-2 levels showed a significant elevation from E15 to E16 and E16 to E17. This suggests the regulation of extracellular matrix is likely to be of importance in palate morphogenesis.
唇腭裂是人类常见的颅面畸形。其病因是多因素的，尚不明确。由于胶原蛋白是发育中腭部的主要结构成分，我们研究了其在大鼠腭突形成和上抬过程中的组成和代谢。在胚胎第15、16和17天以及产后采集腭突。腭部胶原蛋白从胚胎第15天到第17天增加了两倍，从胚胎第17天到出生后5天的幼崽增加了10倍。腭部钙化主要出现在产后。胶原蛋白交联在腭突上抬和融合中可能很重要，其情况有所不同。羟赖氨酸吡啶酮交联的浓度在腭突上抬之前最高，此后下降。同样，二羟基赖氨酸正亮氨酸的最高浓度出现在胚胎第16天，这支持了顺应性间充质腭突对内在上抬力作出反应的概念。然后我们确定负责基质降解的酶，即基质金属蛋白酶（MMP）和金属蛋白酶组织抑制剂（TIMP）在同一时期是否发生变化。分别通过明胶酶谱法和反向酶谱法鉴定MMP-2以及TIMP-1和TIMP-2。用荧光底物分析法测定MMP-3活性。从胚胎第15天到第17天，TIMP-1、TIMP-2和MMP-3水平保持恒定。MMP-2水平从胚胎第15天到第16天以及从胚胎第16天到第17天显著升高。这表明细胞外基质的调节在腭部形态发生中可能很重要。
