同步辐射技术对大鼠腰椎小关节退变的三维可视化研究

Three-dimensional visualization of lumbar facet joint degeneration by using synchrotron radiation-based propagation phase contrast micro-tomography

中文关键词:  同步辐射  相位衬度成像  腰椎小关节  三维可视化

英文关键词:Synchrotron radiation  Phase contrast imaging  Lumbar facet joint  Three-dimensional visualization

中文摘要:

  【摘要】 目的：利用同步辐射相衬成像技术（synchrotron radiation propagation phase contrast micro-tomography，SR-PPCT）对大鼠腰椎小关节（lumbar facet joint，LFJ）的解剖微结构进行三维可视化观测及量化分析，探讨小关节源性腰痛（low back pain，LBP）的潜在机制。方法：取成年（对照组）和老化（实验组）SD大鼠L4/5小关节，经多聚甲醛固定、梯度脱水后于上海光源X射线成像与生物医学应用（BL13W1）光束线站进行扫描。采用独立样本t检验比较两组大鼠LFJ间软骨、软骨下骨板、松质骨、关节间隙的差异。结果：成年组大鼠LFJ关节间隙为38.00±4.50μm，软骨厚度为15.6±0.63μm，软骨体积为（51.25±1.49）×104μm3，软骨下骨板厚度为16.37±1.23μm，软骨下骨骨体积分数（BV/TV）为（60±5）%，表面积体积分数（BS/TV）为180±20mm-1，松质骨骨小梁数量（TbN）为6.85±0.31mm-1；老化组LFJ关节间隙为16.25±0.85μm，软骨厚度为18.90±2.14μm，软骨体积为（37.00±1.83）×104μm3，软骨下骨板厚度为72.48±3.14μm，软骨下骨骨体积分数（BV/TV）为（87±4）％，表面积体积分数（BS/TV）为0.97±0.08mm-1，松质骨骨小梁数量（TbN）为2.07±0.21mm-1；与成年组相比，老化组大鼠LFJ关节间隙变窄（P＜0.05）、软骨容量减低（P＜0.05），软骨厚度改变无统计学差异（P＞0.05）、软骨下骨骨板增厚（P＜0.05），孔隙状结构消失，松质骨骨小梁数量减少（P＜0.05）。结论：SR-PPCT可实现软骨和软骨下骨的同时高精度三维可视化观测；LFJ退变过程中软骨和软骨下骨形态均发生明显改变。

英文摘要:

  【Abstract】 Objectives: To investigate the three-dimensional morphology of lumbar facet joint(LFJ) in rats using synchrotron radiation-based propagation phase contrast micro-tomography(SR-PPCT), and to discover the potential mechanism of lumbar zygapophysial joint pain. Methods: L4/5 LFJs were harvested from healthy SD rats of young and aging group respectively. The specimens were scanned by SR-PPCT at BL13W1 of Shanghai Synchrotron Radiation Facility(SSRF) in China. The three-dimensional visualization images of LFJs were reconstructed by VG Studio Max for further analysis. Independent sample t test was used to compare the differences of LFJ cartilage, subchondral bone plate, cancellous bone and joint space between two groups of rats. Results: The joint space, cartilage thickness, cartilage volume, subchondral bone plate thickness, subchondral bone(BV/TV), (BS/TV) and cancellous bone(TbN) of young group′s LFJs were 38.00±4.50μm, 15.6±0.63μm, (51.25±1.49)×104μm3, 16.37±1.23μm, (60±5)%, 180±20mm-1, 6.85±0.31mm-1 respectively. The data LFJs of aging group were 16.25±0.85μm, 18.90±2.14μm, (37.00±1.83)×104μm3, 72.48±3.14μm, (87±4)%, 0.97±0.08mm-1, 2.07±0.21mm-1. Compared with the young group, the LFJs of aging group′s joint space was narrowed, the cartilage volume was decreased, the subchondral bone plate became thicker, the void-like structure gradually disappeared, and the number of trabecular bone in the subchondral was decreased. Conclusions: Synchrotron radiation phase contrast imaging enables the simultaneous visualization of both cartilage and subchondral bone with high precision. During LFJ degeneration, subchondral bone changes appear in parallel to the cartilage degeneration, and the changes in one component (cartilage or subchondral bone) cause adaptive changes.