Maclean Jeffery J, Lee Cynthia R, Alini Mauro, Iatridis James C
Department of Mechanical Engineering, University of Vermont, 231B Votey Building, 33 Colchester Avenue, Burlington 05405-0156, USA.
J Orthop Res. 2004 Nov;22(6):1193-200. doi: 10.1016/j.orthres.2004.04.004.
The goal of this study was to characterize the anabolic and catabolic mRNA response of the disc to dynamic loading to determine if variations in the magnitude and/or frequency of loading could elicit different cellular responses. Sixty-eight Wistar rats were instrumented with an Ilizarov-type device spanning caudal disc 8-9. Seventy-two hours after surgery, animals were anesthetized and loaded at either 1 or 0.2 MPa at a frequency of 1, 0.2 or 0.01 Hz for 2 h (6 groups). The surgical control (Sham) animals underwent anesthesia with no loading. Loaded (c8-9) and internal-control discs (c6-7 and c10-11) were dissected and annulus and nucleus tissue were separately analyzed by real-time RT-PCR for levels of anabolic (collagen-1A1, collagen-2A1, aggrecan) and catabolic (MMP-3, MMP-13, ADAMTs-4) mRNA. In the nucleus, a frequency-dependent response was seen at 1 MPa with anabolic genes stimulated at 0.01 Hz and catabolic genes at 1 Hz. In the annulus all frequencies resulted in significant up-regulation of catabolic mRNA at 1 MPa loading. In general loading at 0.2 MPa or 0.2 Hz had little effect on gene expression. The results suggest that gene expression of the annulus appears to be more dependent on the magnitude of applied stress, while the nucleus is both magnitude- and frequency-dependent.
本研究的目的是描述椎间盘对动态负荷的合成代谢和分解代谢mRNA反应，以确定负荷大小和/或频率的变化是否会引发不同的细胞反应。68只Wistar大鼠安装了跨越尾椎8 - 9椎间盘的伊利扎洛夫式装置。术后72小时，动物麻醉后分别以1或0.2 MPa的压力、1、0.2或0.01 Hz的频率加载2小时（共6组）。手术对照组（假手术）动物仅接受麻醉而不加载。对加载的（c8 - 9）椎间盘和内部对照椎间盘（c6 - 7和c10 - 11）进行解剖，通过实时RT - PCR分别分析纤维环和髓核组织中合成代谢（胶原蛋白 - 1A1、胶原蛋白 - 2A1、聚集蛋白聚糖）和分解代谢（基质金属蛋白酶 - 3、基质金属蛋白酶 - 13、含血小板解聚蛋白样金属蛋白酶 - 4）mRNA的水平。在髓核中，1 MPa压力下观察到频率依赖性反应，合成代谢基因在0.01 Hz时受到刺激，分解代谢基因在1 Hz时受到刺激。在纤维环中，所有频率在1 MPa负荷下均导致分解代谢mRNA显著上调。一般来说，0.2 MPa或0.2 Hz的负荷对基因表达影响很小。结果表明，纤维环的基因表达似乎更依赖于施加应力的大小，而髓核则同时依赖于应力大小和频率。
