Murakami Hideki, Yoon S Tim, Attallah-Wasif Emad S, Tsai Kai-Jow, Fei Qinming, Hutton William C
Department of Orthopaedic Surgery, Iwate Medical University School of Medicine, Morioka, Japan.
Spine (Phila Pa 1976). 2006 Jul 15;31(16):1770-4. doi: 10.1097/01.brs.0000227255.39896.f3.
Quantitative analysis of endogenous messenger ribonucleic acid (mRNA) expression of anabolic cytokines in the anulus fibrosus and nucleus pulposus tissue from the intervertebral discs of young and old rabbits was performed.
To measure the expression of anabolic cytokines bone morphogenetic protein-2 (BMP-2), BMP-7, transforming growth factor-beta (TGF-beta), and insulin-like growth factor-I (IGF-I) in the anulus fibrosus and nucleus pulposus tissue from young and old rabbits to determine if there are differences with age.
Disc degeneration increases with age and is associated with compromised disc chondrocytic function. Molecules such as BMP-2, BMP-7, TGF-beta, and IGF-I are known to up-regulate disc cell synthesis of key chondrocytic matrix molecules in vitro, and have been proposed as therapeutic agents to prevent disc degeneration. Previous studies have shown that exogenous anabolic cytokines can up-regulate disc-cell function both in vitro and in vivo, however, the endogenous expression of anabolic cytokines in the disc is still unknown.
New Zealand white rabbits aged 3 years (old) and 6 months (young) were used. Quantitative real-time polymerase chain reaction was performed to measure the mRNA levels of BMP-2, BMP-7, TGF-beta1, and IGF-I from anulus fibrosus and nucleus pulposus tissue from young and old rabbits. The discs form the young rabbits represent nondegenerated discs, and the discs from the old rabbits represent discs at the onset of degeneration.
In the nucleus pulposus, the mRNA levels, given as a ratio of old to young, were 3.6 for BMP-2 (P = 0.004), 61 for BMP-7 (P = 0.02), 4.0 for TGF-beta1 (P = 0.3), and 0.6 for IGF-I (P = 0.2). In the anulus fibrosus, the mRNA levels, given as a ratio of old to young, were 1.6 for BMP-2 (P = 0.07), 4.6 for BMP-7 (P = 0.004), 2.9 for TGF- beta1 (P = 0.01), and 2.0 for IGF-I (P = 0.1).
The disc tissue from the old rabbits as compared to the young rabbits showed, in general, significantly higher mRNA levels of endogenous BMP-2, BMP-7, and TGF-beta in both the anulus fibrosus and nucleus pulposus. The similar patterns of up-regulation in gene expression with age shown by these 3 anabolic cytokines suggest a common pathway in terms of regulation and transcription in the early stage of disc degeneration. The knowledge of the age-related pattern in endogenous gene expression of these anabolic cytokines could provide important information for clinical interventional therapy.
对年轻和老年兔椎间盘纤维环和髓核组织中合成代谢细胞因子的内源性信使核糖核酸（mRNA）表达进行定量分析。
测量年轻和老年兔椎间盘纤维环和髓核组织中合成代谢细胞因子骨形态发生蛋白-2（BMP-2）、BMP-7、转化生长因子-β（TGF-β）和胰岛素样生长因子-I（IGF-I）的表达，以确定是否存在年龄差异。
椎间盘退变随年龄增加而加重，且与椎间盘软骨细胞功能受损有关。已知BMP-2、BMP-7、TGF-β和IGF-I等分子可在体外上调椎间盘细胞关键软骨细胞基质分子的合成，并已被提议作为预防椎间盘退变的治疗药物。先前的研究表明，外源性合成代谢细胞因子在体外和体内均可上调椎间盘细胞功能，然而，椎间盘内合成代谢细胞因子的内源性表达仍不清楚。
使用3岁（老年）和6个月（年轻）的新西兰白兔。采用定量实时聚合酶链反应测量年轻和老年兔椎间盘纤维环和髓核组织中BMP-2、BMP-7、TGF-β1和IGF-I的mRNA水平。年轻兔的椎间盘代表未退变的椎间盘，老年兔的椎间盘代表退变初期的椎间盘。
在髓核中，以老年与年轻的比值表示的mRNA水平，BMP-2为3.6（P = 0.004），BMP-7为61（P = 0.02），TGF-β1为4.0（P = 0.3），IGF-I为0.6（P = 0.2）。在纤维环中，以老年与年轻的比值表示的mRNA水平，BMP-2为1.6（P = 0.07），BMP-7为4.6（P = 0.004），TGF-β1为2.9（P = 0.01），IGF-I为2.0（P = 0.1）。
与年轻兔相比，老年兔的椎间盘组织在纤维环和髓核中内源性BMP-2、BMP-7和TGF-β的mRNA水平总体上显著更高。这三种合成代谢细胞因子随年龄增长呈现出相似的基因表达上调模式，提示在椎间盘退变早期的调控和转录方面存在共同途径。了解这些合成代谢细胞因子内源性基因表达的年龄相关模式可为临床干预治疗提供重要信息。
