University of Athens, Third Department of Orthopaedic Surgery, KAT Hospital and Medical School, Athens, Greece.
University of Patras, Laboratory of Molecular Pharmacology, School of Health Sciences, Greece.
Bone Joint Res. 2014 Sep;3(9):273-9. doi: 10.1302/2046-3758.39.2000326.
The aim of this study was to examine whether asymmetric loading influences macrophage elastase (MMP12) expression in different parts of a rat tail intervertebral disc and growth plate and if MMP12 expression is correlated with the severity of the deformity.
A wedge deformity between the ninth and tenth tail vertebrae was produced with an Ilizarov-type mini external fixator in 45 female Wistar rats, matched for their age and weight. Three groups were created according to the degree of deformity (10°, 30° and 50°). A total of 30 discs and vertebrae were evaluated immunohistochemically for immunolocalisation of MMP12 expression, and 15 discs were analysed by western blot and zymography in order to detect pro- and active MMP12.
No MMP12 expression was detected in the nucleus pulposus. Expression of MMP12 in the annulus progressively increased from group I to groups II and III, mainly at the concave side. Many growth plate chondrocytes expressed MMP12 in the control group, less in group I and rare in groups II and III. Changes in cell phenotype and reduction of cell number were observed, together with disorganisation of matrix microstructure similar to disc degeneration. ProMMP12 was detected at the area of 54 kDa and active MMP12 at 22 kDa.
Expression of MMP12 after application of asymmetric loading in a rat tail increased in the intervertebral disc but decreased in the growth plate and correlated with the degree of the deformity and the side of the wedged disc. Cite this article: Bone Joint Res 2014;3:273-9.
本研究旨在探讨不对称加载是否会影响大鼠尾椎间盘和生长板不同部位的巨噬细胞弹性蛋白酶（MMP12）表达，以及 MMP12 表达是否与畸形严重程度相关。
通过 Ilizarov 型微型外固定器在 45 只雌性 Wistar 大鼠的第 9 和第 10 尾椎之间产生楔形畸形，这些大鼠按年龄和体重匹配。根据畸形程度（10°、30°和 50°）将大鼠分为 3 组。共对 30 个椎间盘和椎体进行免疫组化评估 MMP12 表达的免疫定位，对 15 个椎间盘进行 Western blot 和酶谱分析，以检测 pro-MMP12 和活性 MMP12。
髓核内未检测到 MMP12 表达。MMP12 在椎间盘的环状纤维中表达逐渐增加，从第 I 组到第 II 组和第 III 组，主要在凹侧。对照组中许多生长板软骨细胞表达 MMP12，第 I 组中较少，第 II 组和第 III 组中罕见。观察到细胞表型的变化和细胞数量的减少，以及基质微结构的紊乱，类似于椎间盘退变。在 54 kDa 处检测到 pro-MMP12，在 22 kDa 处检测到活性 MMP12。
不对称加载应用于大鼠尾巴后，椎间盘内 MMP12 的表达增加，而生长板内 MMP12 的表达减少，与畸形程度和楔形椎间盘的侧方相关。
Bone Joint Res 2014;3:273-9.
