Al-Mubarak Rasha, Da Silveira Adriana, Mao Jeremy J
Tissue Engineering Laboratory, University of Illinois at Chicago, MC 841, Chicago, IL 60612-7211, USA.
Cell Tissue Res. 2005 Sep;321(3):465-71. doi: 10.1007/s00441-005-1136-2. Epub 2005 Jul 27.
Craniofacial sutures create a soft tissue interface between various calvarial and facial bones. Facial and cranial sutures show differences in their surrounding anatomical structures and local mechanical strain environments. Despite previous attempts to identify the expression of matrix metalloproteinase genes (MMPs) in cranial sutures, little is known regarding whether facial and cranial sutures differ in MMP expression. We have investigated the expression of MMP-1 and MMP-2 in the pre-maxillomaxillary suture (PMS; facial suture) and the frontoparietal suture (FPS; cranial suture) in 32-day-old rats with or without the application of cyclic loading. Expression of MMP-1 and MMP-2 was detected by the reverse transcription/polymerase chain reaction technique. At 32 days of postnatal development (n=6), both MMP-1 and MMP-2 were reproducibly expressed in the facial PMS, in comparison with negligible MMP-1 and MMP-2 expression in the cranial FPS. In six age- and sex-matched control rats, cyclic loading at 4 Hz and 1000 mN was applied to the maxilla for two 20-min episodes within a 12-h interval. In some (but not all) cases, cyclic loading induced marked expression of MMP-1 and MMP-2 in the PMS and FPS in comparison with corresponding non-loaded controls. These data confirm our previous finding that short doses of cyclic loading upregulate MMP-2 expression in craniofacial sutures and suggest the possibility that facial and cranial sutures differ in matrix degradation rates during postnatal development.
颅面骨缝在各种颅骨和面部骨骼之间形成了一个软组织界面。面部和颅骨骨缝在其周围的解剖结构和局部机械应变环境方面存在差异。尽管之前有人试图确定基质金属蛋白酶基因（MMPs）在颅骨骨缝中的表达，但对于面部和颅骨骨缝在MMP表达上是否存在差异却知之甚少。我们研究了在32日龄大鼠中，施加或不施加循环载荷情况下，上颌前颌骨缝（PMS；面部骨缝）和额顶骨缝（FPS；颅骨骨缝）中MMP-1和MMP-2的表达。通过逆转录/聚合酶链反应技术检测MMP-1和MMP-2的表达。在出生后32天（n = 6）时，与颅骨FPS中可忽略不计的MMP-1和MMP-2表达相比，MMP-1和MMP-2在面部PMS中均可重复表达。在6只年龄和性别匹配的对照大鼠中，在12小时的间隔内，以4 Hz和1000 mN的频率对上颌施加两个20分钟的循环载荷。在一些（但不是所有）情况下，与相应的未加载对照相比，循环载荷诱导了PMS和FPS中MMP-1和MMP-2的显著表达。这些数据证实了我们之前的发现，即短剂量的循环载荷会上调颅面骨缝中MMP-2的表达，并提示在出生后发育过程中，面部和颅骨骨缝在基质降解速率上可能存在差异。
