Aigner T, Gresk-otter K R, Fairbank J C, von der Mark K, Urban J P
Department of Pathology, Friedrich-Alexander-University of Erlangen, Nurnberg, FRG.
Calcif Tissue Int. 1998 Sep;63(3):263-8. doi: 10.1007/s002239900524.
The distribution and expression of type X collagen, a calcium-binding collagen, which is a marker of hypertrophic chondrocytes and thought to be involved in cartilage calcification, was examined in situ in nondegenerate (grade I or II) human discs taken at autopsy over a wide age range (fetal->80 years) and also in scoliotic discs removed at surgery. In the fetal vertebral column, type X collagen was strongly expressed in the hypertrophic chondrocytes of the endplate, but was not seen in other areas. In the cartilaginous endplate of adults, it was found over the whole age range examined, with intensity increasing with age. In the disc matrix itself, type X collagen was demonstrated around individual cells from all individuals older than 50 years, but not in any fetal or autopsy disc from individuals younger than 40 years. In scoliotic discs, however, focal type X collagen expression was seen in 3/8 patients younger than 40 years including one 12-year-old. No type X collagen was found in the outer annulus in any autopsy or scoliotic disc, supporting the idea that cells of the outer annulus are phenotypically distinct from cells of the inner annulus and the nucleus. Our results demonstrate for the first time that type X collagen is a possible gene product of the intervertebral disc cells and a potential biochemical component of the disc matrix. They indicate that with age or in scoliosis, some cells from the inner annulus or nucleus of the disc differentiate to the hypertrophic chondrocyte phenotype. This might be the initiating event for the abnormal calcification described in aged and scoliotic discs in other studies.
X型胶原是一种钙结合胶原，是肥大软骨细胞的标志物，被认为参与软骨钙化。我们对取自不同年龄（胎儿至80岁）尸体解剖的非退变（I级或II级）人类椎间盘以及手术切除的脊柱侧弯椎间盘进行了X型胶原分布和表达的原位检测。在胎儿脊柱中，X型胶原在终板的肥大软骨细胞中强烈表达，但在其他区域未见表达。在成人的软骨终板中，在整个检测年龄范围内均有发现，且强度随年龄增加。在椎间盘基质本身，X型胶原在所有50岁以上个体的单个细胞周围均有显示，但在40岁以下个体的任何胎儿或尸体解剖椎间盘中均未发现。然而，在脊柱侧弯椎间盘中，在3/8例40岁以下患者中观察到局灶性X型胶原表达，其中包括一名12岁患者。在任何尸体解剖或脊柱侧弯椎间盘中，在外环均未发现X型胶原，这支持了外环细胞在表型上与内环和髓核细胞不同的观点。我们的结果首次表明，X型胶原是椎间盘细胞可能的基因产物和椎间盘基质的潜在生化成分。结果表明，随着年龄增长或在脊柱侧弯情况下，椎间盘内环或髓核的一些细胞会分化为肥大软骨细胞表型。这可能是其他研究中描述的老年和脊柱侧弯椎间盘异常钙化的起始事件。
