Department of Orthopaedic Surgery, University of Heidelberg, Germany.
Spine (Phila Pa 1976). 2009 Dec 1;34(25):2730-9. doi: 10.1097/BRS.0b013e3181b723c9.
In vivo animal study.
To describe a new porcine disc degeneration model, and to analyze disc remodeling and degeneration after nucleotomy with special view to the different nucleus pulposus (NP) cell types.
Thus far, predominantly smaller animals were used for disc degeneration models; however, such small discs were inappropriate to investigate cell implementation therapies. Though notochordal cells (NCs) are important for disc formation and maintenance, differences in the amount of NCs between human and animal discs have often been neglected.
Twenty-four Goettingen minipigs underwent partial nucleotomy with a 16G biopsy cannula, to remove approximately 10% of total NP volume. Animals were followed up for 3, or 24 weeks and analyzed by radiographs, MRIs, (immuno)histology, gene expression analysis, and biomechanical testing.
Three weeks after nucleotomy disc height was reduced by 26%, and magnetic resonance imaging signal intensity by 40%. At 24 weeks disc height was decreased by 32%. Increased degenerative changes were found in a histodegeneration score 3 and 24 weeks after nucleotomy, as well as considerable NP scarification after 3 weeks. In controls, cytokeratin-8 immunohistochemistry identified NCs in proximity to chondrocyte-like NP cells at approximately equal ratio. After nucleotomy, NCs were considerably reduced to <10% of total NP cells. Matrix genes were upregulated, except for aggrecan that decreased to 35% of initial values 3 weeks after nucleotomy. Matrix degrading factors (matrix metalloproteinases 13 and 3) were continuously upregulated, whereas transcripts of their inhibitors (tissue inhibitors of matrix metalloproteinase 2 and 3) were downregulated. No significant changes in segmental spinal flexibility or bone density were found after nucleotomy.
We introduced a new disc degeneration model with relatively large discs that could be used for cell therapeutic approaches. The study gives further information about disc remodeling after nucleotomy and indicates the relevance of an altered cellular composition for the development of disc degeneration.
体内动物研究。
描述一种新的猪椎间盘退变模型，并分析髓核切除术后的椎间盘重塑和退变，特别关注不同的髓核细胞类型。
迄今为止，主要使用较小的动物进行椎间盘退变模型研究；然而，如此小的椎间盘不适合研究细胞实施疗法。尽管脊索细胞（NCs）对椎间盘的形成和维持很重要，但人类和动物椎间盘之间 NCs 数量的差异常常被忽视。
24 只哥廷根小型猪接受了 16G 活检套管的部分髓核切除术，以切除大约 10%的总 NP 体积。动物在术后 3 或 24 周进行放射学、磁共振成像（MRI）、（免疫）组织学、基因表达分析和生物力学测试。
髓核切除术后 3 周，椎间盘高度降低 26%，磁共振成像信号强度降低 40%。24 周时，椎间盘高度降低 32%。在组织退变评分 3 级和髓核切除术后 24 周时，发现退行性变化增加，以及 3 周后 NP 明显瘢痕化。在对照组中，细胞角蛋白-8 免疫组织化学鉴定出与软骨样 NP 细胞接近的 NCs，比例大致相等。髓核切除术后，NCs 减少到 NP 细胞总数的<10%。基质基因上调，除了 aggrecan 在髓核切除术后 3 周时降低到初始值的 35%。基质降解因子（基质金属蛋白酶 13 和 3）持续上调，而其抑制剂（基质金属蛋白酶抑制剂 2 和 3）的转录物下调。髓核切除术后，节段性脊柱柔韧性或骨密度无明显变化。
我们引入了一种新的椎间盘退变模型，使用相对较大的椎间盘，可用于细胞治疗方法。该研究进一步提供了髓核切除术后椎间盘重塑的信息，并表明细胞组成的改变与椎间盘退变的发展有关。
