同步辐射X线相衬成像技术在兔髌骨-髌腱连接点纤维软骨细胞的三维可视化应用研究

摘要

Background: Synchrotron radiation-based X-ray phase-contrast computed tomography (SR-XPCT) is an advanced tool for nondestructive analysis of three dimensional inner microstructure of samples, and plays an important part in the researches such as spinal cord microvasculature and lung bronchium.Purpose: This study was to investigate the three-dimensional morphology of fibrochondrocytes in rabbit patella-patellar tendon junction (PPTJ) using SR-XPCT, and develop an advanced imaging method.Methods:Three PPTJs were harvested from healthy mature female New Zealand rabbits. The specimens were scanned by SR-XPCT at BL13W1 of Shanghai Synchrotron Radiation Facility (SSRF) in China. The tomographic image was captured by Charge Coupled Device (CCD) detector with a 0.65-μm resolution. The three-dimensional visualization images of PPTJ were reconstructed by VG Studio Max. After that, the specimens were embedded by paraffin for Safranin O/Fast-green staining.Results:High-resolution three-dimensional visualization images of PPTJ and the parameters of the chondrocytes in fibrocartilage zone were successfully obtainedvia the SR-XPCT. With spherical and ellipsoidal morphologic features and its configuration characteristics in three dimension, the fibrochondrocytes revealed by SR-XPCT were consistent with the results of traditional histological staining. The parameters of chondrocytes showed that the mean diameter of chondrocyte was (10.139±1.265)μm, the mean volume was (291.187±87.283)μm3 and 75.4% of the chondrocytes’ volume ranged from 200μm3 to 400μm3, the mean sphericity degree was 0.711±0.079, and 84.9% of chondrocytes’ sphericity degree ranged from 0.605 to 0.805.Conclusion:The three-dimensional microstructure of the PPTJ was intuitively, accurately and undistortedly realized by the SR-XPCT, which may act as a novel instrument to access the three-dimensional microstructure changes during the PPTJ healing process.%利用同步辐射X射线相衬成像技术(Synchrotron Radiation-based X-ray Phase-contrast Computed Tomography, SR-XPCT)对兔髌骨-髌腱连接点(Patella-Patellar Tendon Junction, PPTJ)移行区的纤维软骨细胞进行三维可视化及量化表征。正常骨成熟的新西兰PPTJ经多聚甲醛固定、梯度酒精脱水后，于上海光源X射线成像与生物医学应用光束线站进行扫描；采集的原始图像经数字减影、相位恢复、切片重构、位数转换后进行三维重构分析；标本扫描后进行传统组织学验证。SR-XPCT 能成功获取 PPTJ 及其移行区纤维软骨细胞的三维高清图像，并对移行区纤维软骨细胞进行了量化表征：平均直径为(10.139±1.265)mm；平均体积为(291.187±87.283)μm3，体积分布在200−400μm3之间的占75.4%；平均球形度为0.711±0.079，球形度在0.605−0.805之间的纤维软骨细胞约占84.9%。SR-XPCT作为一种先进的、直观准确的可视化骨腱连接点的三维微观形态结构研究方法，为骨腱连接点损伤修复的三维形态学研究提供了新方法、新思路。