Eid Karim, Thornhill Thomas S, Glowacki Julie
Department of Orthopedic Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, USA.
J Orthop Res. 2006 May;24(5):1062-8. doi: 10.1002/jor.20137.
Osteoarthritis is characterized by a progressive degradation of cartilage structure and function. This study tests the hypothesis that disease severity is characterized by alterations in expression of cartilage-specific genes for aggrecan and collagen type II. Cartilage, discarded from six subjects undergoing knee replacement, was subdivided into homogeneous portions by the surgeon according to the Outerbridge classification. For four subjects, it was possible to separate the tissue into two or three fractions with different disease severity. Portions of each sample were prepared either for histological analysis and ranking according to the Mankin system or for RNA extraction. Quantitative, competitive RT-PCR assays were used for measurement of mRNA for aggrecan, collagen type II, and glyceraldehyde-3-phosphate dehydrogenase. Clinical grading was correlated with histological score (Spearman r = 0.60, p = 0.043). There was a striking decrease in expression of aggrecan and collagen II that was correlated with increase in the grade in regions of cartilage within an individual subject. In the series of 12 samples, there was an inverse correlation between aggrecan expression and osteoarthritis grade (Spearman r = -0.59, p = 0.042). In conclusion, there was an inverse relationship between regional disease severity in osteoarthritis and expression of aggrecan. Use of quantitative, competitive RT-PCR is practical for assessment of chondrocyte gene signatures.
骨关节炎的特征是软骨结构和功能的逐渐退化。本研究检验了以下假设：疾病严重程度的特征是软骨特异性基因聚集蛋白聚糖和II型胶原表达的改变。从六名接受膝关节置换的受试者身上丢弃的软骨，由外科医生根据Outerbridge分类法细分为均匀的部分。对于四名受试者，可以将组织分离成两到三个具有不同疾病严重程度的部分。每个样本的部分用于组织学分析并根据Mankin系统进行评分，或用于RNA提取。采用定量竞争性逆转录-聚合酶链反应（RT-PCR）测定法测量聚集蛋白聚糖、II型胶原和甘油醛-3-磷酸脱氢酶的mRNA。临床分级与组织学评分相关（Spearman秩相关系数r = 0.60，p = 0.043）。在单个受试者的软骨区域内，聚集蛋白聚糖和II型胶原的表达显著下降，且与分级增加相关。在这一系列的12个样本中，聚集蛋白聚糖表达与骨关节炎分级呈负相关（Spearman秩相关系数r = -0.59，p = 0.042）。总之，骨关节炎局部疾病严重程度与聚集蛋白聚糖表达之间存在负相关关系。使用定量竞争性RT-PCR对于评估软骨细胞基因特征是可行的。
