Melrose J, Ghosh P, Taylor T K, Latham J, Moore R
Raymond Purves Bone and Joint Research Laboratories, University of Sydney, Royal North Shore Hospital of Sydney, St. Leonards, New South Wales, Australia.
J Spinal Disord. 1997 Feb;10(1):55-67.
An established model of experimental disc degeneration (Osti et al., Spine 15:762, 1990; Melrose et al., J Orthop Res 10:655, 1992) was used in this study. Four 2-year-old sheep received anterolateral incisions (4 x 10 mm) in the outer one-third of the annulus fibrosus of their L2-L3 and L4-L5 discs (lesion group). The annulus was not incised in another four sham-operated animals. After 6 months the sheep were killed, lumbar discs were dissected into lateral halves of the annulus fibrosus and the nucleus pulposus. Cells were isolated from disc tissues enzymatically and were grown in alginate bead culture to examine the proteoglycan metabolism of cells from lesion and control zones. The media of lesion zone cultures contained relatively high levels (compared with sham cultures) of catabolic fragments of the large, high-buoyant-density proteoglycans as demonstrated by Western blotting using monoclonal antibodies (5-D-4, 3-B-3, 1-C-6) and biotinylated hyaluronan and also by gel chromatography. Furthermore, cells from the vicinity of the lesion site also synthesized significantly lower levels (compared with sham cultures) of aggrecan that was retained within the alginate beads. Collectively, these data indicated that focal depletion of large, high-buoyant-density proteoglycans was evident within lesion sites in this model of experimental disc degeneration. The introduction of an annular lesion therefore significantly affected the proteoglycan metabolism of endogenous disc cell populations. The unique hydrodynamic and viscoelastic properties of the intervertebral disc are dependent to a large degree on the tissue levels of aggrecan. The focal depletion of aggrecan by annular lesions therefore may represent an important predisposing factor to the subsequent degeneration of these intervertebral discs.
本研究采用了一种已确立的实验性椎间盘退变模型（Osti等人，《脊柱》15:762，1990；Melrose等人，《矫形外科学研究杂志》10:655，1992）。4只2岁的绵羊在其L2-L3和L4-L5椎间盘纤维环外三分之一处接受前外侧切口（4×10毫米）（损伤组）。另外4只假手术动物的纤维环未切开。6个月后处死绵羊，将腰椎间盘解剖为纤维环外侧半部分和髓核。通过酶法从椎间盘组织中分离细胞，并在藻酸盐珠培养中生长，以检查损伤区和对照区细胞的蛋白聚糖代谢。如使用单克隆抗体（5-D-4、3-B-3、1-C-6）和生物素化透明质酸的蛋白质印迹法以及凝胶色谱法所示，损伤区培养物的培养基中含有相对较高水平（与假手术培养相比）的大的、高浮力密度蛋白聚糖的分解代谢片段。此外，损伤部位附近的细胞合成并保留在藻酸盐珠内的聚集蛋白聚糖水平也显著低于假手术培养组。总体而言，这些数据表明，在该实验性椎间盘退变模型的损伤部位，大的、高浮力密度蛋白聚糖明显局部耗竭。因此，环形损伤的引入显著影响了内源性椎间盘细胞群的蛋白聚糖代谢。椎间盘独特的流体动力学和粘弹性特性在很大程度上取决于聚集蛋白聚糖的组织水平。因此，环形损伤导致的聚集蛋白聚糖局部耗竭可能是这些椎间盘随后退变的一个重要易感因素。
