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 obtained via 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 200 μm3 to 400 μm3

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.Cited