Zhang Zijun, McCaffery J Michael, Spencer Richard G S, Francomano Clair A
National Institute on Aging, National Institutes of Health, Laboratory of Genetics, 333 Cassell Drive, Suite 3000 Baltimore, MD 21224, USA.
J Orthop Res. 2005 Mar;23(2):433-9. doi: 10.1016/j.orthres.2004.08.028.
Poor integration of neocartilage with recipient has been a major obstacle to articular cartilage restoration. An in vitro study was designed to provide insights regarding the integration process. Cartilage explants and chondrocytes were harvested from the distal sternum of 16-day-old chick embryos. Four million chondrocytes and one 1mm(3) explant were centrifuged together in a 0.75ml tube. In the constructs, consisting of cartilage explant and chondrocyte pellet, isolated chondrocytes attached to the surface of the explant at the beginning of the culture, followed by significant chondrocyte death at the interface between chondrocyte pellet and explant. Chondrocyte apoptosis was seen almost exclusively at this interface. Meanwhile, the interface was a zone with active extracellular matrix deposition as demonstrated by immunohistochemistry. By two weeks, the junction of neocartilage and native cartilage explant had formed an acellular zone with collagen fibrils orientated parallel with the surface of the cartilage explant. In conclusion, chondrocyte death leads to acellularity and fibril network reorganization at the neocartilage/explant interface, and impacts the quality of cartilage repair as abnormal matrix remodeling implies.
新软骨与受体的整合不佳一直是关节软骨修复的主要障碍。一项体外研究旨在深入了解整合过程。从16日龄鸡胚的远端胸骨采集软骨外植体和软骨细胞。将400万个软骨细胞和一个1立方毫米的外植体在一个0.75毫升的试管中一起离心。在由软骨外植体和软骨细胞团块组成的构建物中，分离的软骨细胞在培养开始时附着在外植体表面，随后在软骨细胞团块与外植体的界面处出现大量软骨细胞死亡。软骨细胞凋亡几乎仅见于此界面。同时，免疫组织化学显示该界面是一个细胞外基质活跃沉积的区域。到两周时，新软骨与天然软骨外植体的交界处形成了一个无细胞区，胶原纤维与软骨外植体表面平行排列。总之，软骨细胞死亡导致新软骨/外植体界面处出现无细胞状态和纤维网络重组，并如异常基质重塑所暗示的那样影响软骨修复质量。
