Shanghai Key Laboratory of Orthopaedic Implant, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai 200011, PR China.
BMC Musculoskelet Disord. 2013 Dec 18;14:357. doi: 10.1186/1471-2474-14-357.
To investigate the potential of T2 mapping for characterizing the process of intervertebral disc degeneration (IDD) in a rabbit model.
Thirty-five rabbits underwent an annular stab to the L4/5 discs (L5/6 discs served as internal normal controls). Degenerative changes were graded according to the modified Thompson classification and quantified in T2 respectively at pre-operation, 1, 3, 6, 12 and 24 weeks postoperatively. After MRI analysis, expression analysis of aggrecan and type II collagen gene in nucleus pulposus (NP) was performed using real time polymerase chain reaction (real-time PCR). The longitudinal changes in NP T2 and gene expressions were studied by repeated measures and ANOVA, linear regression was performed for their correlations through the process of IDD. The reliability analysis of method of measurement of NP T2 was also performed.
There was a strong inverse correlation between NP T2 and Thompson grades (r = -0.85). The decline of L4/5 NP T2 through 24 weeks was nonlinear, the most significant decrease was observed in 3 weeks postoperatively (P<0.05). The tendency was confirmed at gene expression levels. NP T2 correlated strongly with aggrecan (R² = 0.85, P<0.01) and type II collagen (R² = 0.78, P<0.01) gene expressions. The intraclass correlation coefficients for interobserver and intraobserver reliability were 0.963 and 0.977 respectively.
NP T2 correlates well with aggrecan and type II collagen gene expressions. T2 mapping could act as a sensitive, noninvasive tool for quantitatively characterizing the process of IDD in longitudinal study, help better understanding of the pathophysiology of IDD, assist us to detect the degenerative cascade, and develop a T2-based quantification scale for evaluation of IDD and efficacy of therapeutic interventions.
探讨 T2 映射在兔模型中表征椎间盘退行性变（IDD）过程的潜力。
35 只兔子接受 L4/5 椎间盘环形刺伤（L5/6 椎间盘作为内部正常对照）。根据改良的 Thompson 分级对退行性改变进行分级，并分别在术前、术后 1、3、6、12 和 24 周进行 T2 定量分析。MRI 分析后，采用实时聚合酶链反应（real-time PCR）对髓核（NP）中聚集蛋白聚糖和 II 型胶原基因的表达进行分析。通过重复测量和方差分析研究 NP T2 和基因表达的纵向变化，通过 IDD 过程进行线性回归分析它们之间的相关性。还对 NP T2 的测量方法进行了可靠性分析。
NP T2 与 Thompson 分级呈强负相关（r=-0.85）。NP T2 在 24 周内呈非线性下降，术后 3 周下降最为明显（P<0.05）。基因表达水平也证实了这一趋势。NP T2 与聚集蛋白聚糖（R²=0.85，P<0.01）和 II 型胶原（R²=0.78，P<0.01）基因表达呈强相关。观察者间和观察者内的组内相关系数分别为 0.963 和 0.977。
NP T2 与聚集蛋白聚糖和 II 型胶原基因表达密切相关。T2 映射可以作为一种敏感、无创的工具，用于在纵向研究中定量描述 IDD 过程，有助于更好地了解 IDD 的病理生理学，协助我们检测退行性级联反应，并开发基于 T2 的定量评分标准来评估 IDD 和治疗干预的疗效。
