双侧小关节切除制作大鼠颈椎间盘退变模型的可行性

Cervical disc degeneration induced by bilateral facetectomy in rats

中文关键词:  【关键词】 椎间盘退变  软骨终板  关节突切除  缺损  大鼠

英文关键词:【Key words】 Disc degeneration  Cartilage endplate  Facetectomy  Lesion  Rats

中文摘要:

  【摘要】 目的：探讨双侧小关节切除建立大鼠颈椎间盘退变模型的可行性。方法：16只3月龄雌性SD大鼠随机均分为实验组和对照组。实验组大鼠C4/5和C5/6双侧上、下关节突采用磨钻切除。术后12周时获取大鼠C4~C6标本。显微CT扫描C5/6节段，测量椎间高度及软骨终板的缺损率，并观测C5椎体微结构的变化；番红O快绿染色后观察髓核和纤维环的形态，并对椎间盘退变程度评分。采用RT-PCR法检测C4/5椎间盘组织中蛋白聚糖、Ⅱ型胶原以及基质金属蛋白酶（MMP）3和13的mRNA表达水平。组间定量指标行独立样本t检验，显著性水平为P<0.05。结果：术后12周，实验组椎间高度为0.51±0.04mm，显著低于对照组（0.55±0.02mm）（P<0.05）。实验组软骨终板出现明显的缺损，下终板缺损主要出现在腹侧，而上终板四周及中央均出现缺损；实验组的缺损率为（11.5±2.0）%，显著大于对照组的（6.9±1.0）%（P<0.05）。在椎体微结构中，实验组骨体积分数和骨小梁间隙分别为（53.0±6.0）%和170±2μm，而对照组分别为（46.4±3.0）%和195±1μm，两组间的差异均有统计学意义。实验组的骨小梁数目和厚度与对照组无统计学差异。组织学观察到实验组椎间盘的软骨终板形态不规则、出现缺损及少许钙化，髓核细胞出现聚集、数量减少，纤维环排列紊乱。实验组椎间盘退变评分为8.6±0.8分，显著高于对照组的5.8±0.5分。在实验组椎间盘组织中，蛋白聚糖和Ⅱ型胶原的mRNA表达水平明显低于对照组，MMP-13的mRNA表达水平显著高于对照组，MMP-3则呈现上升趋势。结论：大鼠颈椎双侧小关节切除可导致切除节段椎间盘在形态学、组织学和分子生物学上的退变，是建立椎间盘退变模型的一种可行方法。

英文摘要:

  【Abstract】 Objectives: To investigate an animal model of intervertebral disc degeneration induced by bilateral facetectomy. Methods: Sixteen Sprague-Dawley female rats with the age of 3 months were assigned evenly and randomly into experimental and control group. The C4/5 and C5/6 bilateral facet joints were sectioned by using a burr in the experimental group. The C4-C6 spinal samples were harvested at 12 weeks after surgery. The C5/6 segments were scanned by using micro-CT and stained with Safranine O/fast green. The intervertebral disc height(IDH), the microstructure of C5 vertebral body, ratio of cartilage endplate lesion(CEL) area to the whole endplate area and disc degeneration score were calculated. The mRNA expression of aggrecan, type Ⅱ collagen(Col2α1), matrix metalloprotease(MMP)-3 and MMP-13 in C4/5 disc were analyzed by using real-time PCR. The statistical significance between groups was determined by using the independent t test with significant difference level at P<0.05. Results: The IDH following facetectomy was significantly lower than that in the control(0.51±0.04mm vs 0.55±0.02mm), and the CEL was greater than that in the control(11.5±2% vs 6.9±1%). The CEL appeared on the ventral side of the inferior endplate, and defect area was noted at peripheral and central of upper endplate. There was a significant increase of BV/TV and Th.Sp following facetectomy. Histological results showed the cartilage endplate lesions and few calcification. The disorganized annular fibers, shrinked nucleus pulposus and less cells in the nucleus pulposus were observed in the discs following facetectomy. The disc degeneration score was 8.6±0.8 and 5.8±0.5 in the experimental group and control group, respectively, and the difference between 2 groups was significant. There was a significantly down-regulated expression of aggrecan and col2α1 while significantly up-regulated expression of MMP-13. Conclusions: Bilateral facetectomy will lead to the disc degeneration of cervical spine not only in morphology, but also in histology and molecular biology, which is a reliable rat model for disc degeneration.