Grivas Theodoros B, Vasiliadis Elias S, Kaspiris Angelos, Khaldi Lubna, Kletsas Dimitris
Orthopaedic Department, "Tzanio" General Hospital, Piraeus, Greece.
Scoliosis. 2011 May 9;6(1):9. doi: 10.1186/1748-7161-6-9.
A scoliotic deformity on intervertebral discs may accelerate degeneration at a molecular level with the production of metalloproteinases (MMPs). In the present experimental study we evaluated the presence of MMP-1 immunohistochemically after application of asymmetric forces in a rat intervertebral disc and the impact of the degree of the deformity on MMP-1 expression.
MATERIAL-METHOD: Thirty female Wistar rats (aged 2 months old, weighted 200 ± 10 grams) were used. All animals were age, weight and height matched. A mini Ilizarov external fixator was applied at the base of a rat tail under anaesthesia in order to create a scoliotic deformity of the intervertebral disc between the 9th and 10th vertebrae. Rats were divided into three groups according to the degree of the deformity. In group I, the deformity was 10°, in group II 30° and in group III 50°. The rats were killed 35 days after surgery. The discs were removed along with the neighbouring vertebral bodies, prepared histologically and stained immunohistochemically. Immunopositivity of disc's cells for MMP-1 was determined using a semi-quantitative scored system.
MMP-1 immunopositivity was detected in disc cells of annulus fibrosus of all intervertebral disc specimens examined. The percentage of MMP-1 positive disc cells in annulus fibrosus in group I, II and III were 20%, 43% and 75%, respectively. MMP-1 positivity was significantly correlated with the degree of the deformity (p < 0,001). An increase of chondrocyte-like disc cells was observed in the outer annulus fibrosus and at the margin of the intervertebral disc adjacent to the vertebral end plates. The difference in the proportion of MMP-1 positive disc cells between the convex and the concave side was statistically not significant in group I (p = 0,6), in group II this difference was statistically significant (p < 0,01). In group III the concave side showed a remarkable reduction in the number of disc's cells and a severe degeneration of matrix microstructure.
The present study showed that an experimentally induced scoliotic deformity on a rat tail intervertebral disc results in over-expression of MMP-1, which is dependent on the degree of the deformity and follows a dissimilar distribution between the convex and the concave side.
椎间盘的脊柱侧弯畸形可能在分子水平上通过金属蛋白酶（MMPs）的产生加速退变。在本实验研究中，我们在大鼠椎间盘施加不对称力后，通过免疫组织化学方法评估MMP - 1的存在情况，以及畸形程度对MMP - 1表达的影响。
使用30只雌性Wistar大鼠（2月龄，体重200±10克）。所有动物在年龄、体重和身高方面相匹配。在麻醉下于大鼠尾巴基部应用小型伊利扎洛夫外固定器，以造成第9和第10椎骨之间椎间盘的脊柱侧弯畸形。根据畸形程度将大鼠分为三组。在第一组中，畸形角度为10°，第二组为30°，第三组为50°。术后35天处死大鼠。取出椎间盘及其相邻椎体，进行组织学制备并进行免疫组织化学染色。使用半定量评分系统确定椎间盘细胞对MMP - 1的免疫阳性情况。
在所检查的所有椎间盘标本的纤维环椎间盘细胞中均检测到MMP - 1免疫阳性。第一组、第二组和第三组纤维环中MMP - 1阳性椎间盘细胞的百分比分别为20%、43%和75%。MMP - 1阳性与畸形程度显著相关（p<0.001）。在纤维环外层和椎间盘与椎体终板相邻边缘观察到软骨样椎间盘细胞增加。第一组中，凸侧和凹侧之间MMP - 1阳性椎间盘细胞比例的差异无统计学意义（p = 0.6），第二组中该差异具有统计学意义（p<0.01）。在第三组中，凹侧椎间盘细胞数量显著减少，基质微观结构严重退变。
本研究表明，实验诱导的大鼠尾巴椎间盘脊柱侧弯畸形导致MMP - 1过度表达，其依赖于畸形程度，且在凸侧和凹侧呈现不同分布。
