Ann Arbor, Mich.; and New York, N.Y. From the Craniofacial Anomalies Program, Section of Plastic Surgery, Department of Surgery, University of Michigan, and the Craniofacial Surgery Program, Department of Surgery, Weill Cornell Medical College.
Plast Reconstr Surg. 2009 Dec;124(6):1840-1848. doi: 10.1097/PRS.0b013e3181bf806c.
The cause of nonsyndromic craniosynostosis remains elusive. Although compressive forces have been implicated in premature suture fusion, conclusive evidence of force-induced craniosynostosis is lacking. The purpose of this study was to determine whether cyclical loading of the murine calvaria could induce suture fusion.
Calvarial coupons from postnatal day-21, B6CBA, wild-type mice (n = 18) were harvested and cultured. A custom appliance capable of delivering controlled, cyclical, compressive loads was applied perpendicular to the sagittal suture within the coupon in vitro. Nine coupons were subjected to 0.3 g of force for 30 minutes each day for a total of 14 days. A control group of nine coupons was clamped in the appliance without loading. Analysis of suture phenotype was performed using alkaline phosphatase and hematoxylin and eosin staining techniques and in situ hybridization analysis using bone sialoprotein.
Control group sagittal sutures-which normally remain patent in mice-showed their customary histologic appearance. In contradistinction, sagittal sutures subjected to cyclic loading showed histologic evidence of premature fusion (craniosynostosis). In addition, alkaline phosphatase activity and bone sialoprotein expression were observed to be increased in the experimental group when compared with matched controls.
An in vitro model of force-induced craniosynostosis has been devised. Premature fusion of the murine sagittal suture was induced with the application of controlled, cyclical, compressive loads. These results implicate abnormal forces in the development of nonsyndromic craniosynostosis, which supports our global hypothesis that epigenetic phenomena play a crucial role in the pathogenesis of craniosynostosis.
非综合征性颅缝早闭的病因仍不清楚。虽然压缩力与过早融合的缝有关，但缺乏力诱导颅缝早闭的确凿证据。本研究的目的是确定周期性加载小鼠颅骨是否能诱导颅缝融合。
从出生后第 21 天的 B6CBA 野生型小鼠的颅骨中取出颅骨标本（n=18）并进行培养。在体外，使用一种可施加可控、周期性、压缩力的定制器械，垂直于颅骨标本中的矢状缝施加力。9 个颅骨标本每天施加 0.3g 的力 30 分钟，共 14 天。9 个颅骨标本被夹在器械中而不加载作为对照组。使用碱性磷酸酶和苏木精-伊红染色技术以及骨涎蛋白的原位杂交分析来分析颅缝表型。
对照组矢状缝-在小鼠中通常保持开放-显示出其常规的组织学外观。相反，接受周期性加载的矢状缝显示出过早融合（颅缝早闭）的组织学证据。此外，与匹配的对照组相比，实验组中碱性磷酸酶活性和骨涎蛋白表达增加。
已经设计了一种力诱导颅缝早闭的体外模型。通过施加可控的、周期性的压缩力，诱导了小鼠矢状缝的过早融合。这些结果表明异常力在非综合征性颅缝早闭的发生中起作用，这支持了我们的总体假说，即表观遗传现象在颅缝早闭的发病机制中起着至关重要的作用。
