A new in utero model for lateral facial clefts
A new in utero model for lateral facial clefts
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DOI：
10.1097/00001665-199711000-00006
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发表时间：
1997-11-01
影响因子：
0.9
通讯作者：
Longaker, MT
中科院分区：
文献类型：
--
作者：
Stelnicki, EJ;Hoffman, WY;Longaker, MT
非典型颅面裂形成的病因尚不清楚。为了验证诸如羊膜带等物理限制力量可以导致这些不寻常的裂隙在器官发生后时期形成的假设，我们对先前报道的羊膜带综合征胎羊模型进行了修改，以检验这些带子对颅面发育的影响。5只妊娠70天的胎羊(足月，140天)通过母体子宫切开术暴露。在每只动物身上，都试图通过将2-O尼龙缝线作为收缩带应用于生长中的面部来制造侧向颅面裂隙。将缝线外固定在颧弓或眶下缘，然后绕圈进入口腔连合。每一条缝线的位置都是为了形成Tessier 5型或Tessier 7型裂隙。五只胎羊中有四只存活到足月。利用该模型可以有效地制作出两种类型的侧方面裂。在每一组中，口腔内收缩带的存在导致了大口畸形的形成，平均口腔连合的侧向位移为7.4 mm。除了这些软组织变化外，每种动物都有部分骨裂(即骨沟)，这是由于限制带在不断生长的面部骨骼上的压力引起的。在两只患有Tessier 7型唇裂的羔羊中，颧弓上出现了不完全的骨裂。在三只带横跨内侧眶下缘的动物中，显著的眶下和颧骨裂隙形成了类似于典型的Tessier 5型面部裂隙。在任何动物身上都没有发现组织坏死、浸渍或溃烂的证据。这些数据首次证明，外力(如羊膜带)对颅面生长的抑制可导致涉及软组织和骨骼元素的侧向面部裂隙的发生。这些畸形很可能是直接束缚正常组织迁移和局部压力增加的组合，后者导致细胞缺血和细胞凋亡。此外，我们的数据表明，这些裂隙可以发生在胎儿发育的后期，即面部生长时期，而不是初级面部形态发生时期。
The etiopathogenesis behind the formation of atypical craniofacial facial clefts remains unknown. To test the hypothesis that physical restricting forces such as amniotic bands can lead to the formation of these unusual clefts in the postorganogenesis period, we have modified a previously reported fetal lamb model of amniotic band syndrome to examine the effects of these bands on craniofacial development. Five 70-day gestation fetal lambs (term, 140 days) were exposed via a maternal hysterotomy. In each animal, an attempt was made to create a lateral craniofacial cleft by applying a 2-O nylon suture as a constriction band to the growing face. The sutures were attached to either the zygomatic arch or the infraorbital rim externally and then looped circumferentially into the oral commissure. Each suture was positioned so as to create either a Tessier type 5 or a Tessier type 7 cleft. Four of five fetal lambs survived to term. Both types of lateral facial clefts were effectively produced using this model. In each group, the presence of an intraoral constriction band led to the formation of macrostomia, with an average 7.4-mm lateral displacement of the oral commissure. In addition to these soft tissue changes, each animal also had partial bony clefting (i.e., a bony groove) induced by the pressure of the restriction band across the growing facial skeleton. In the two lambs with the Tessier type 7 cleft, incomplete bony clefts developed across the zygomatic arch. In three animals with bands placed across the medial infraorbital rim, significant infraorbital and malar bony clefts formed similar to a classic Tessier type 5 facial cleft. No evidence of tissue necrosis, maceration, or ulceration was noted in any animal. These data present, for the first time, evidence that the constriction of craniofacial growth by external forces such as a swallowed amnionic band can lead to the development of lateral facial clefting involving both soft tissue and bony elements. These malformations are likely due to a combination of directly tethering normal tissue migration and an increase in local pressure, which produces cellular ischemia and apoptosis. Furthermore, our data demonstrate that these clefts can occur later in fetal development during a period of facial growth rather than during the period of primary facial morphogenesis.