University of Oulu

Karhula SS, Finnilä MA, Lammi MJ, Ylärinne JH, Kauppinen S, Rieppo L, et al. (2017) Effects of Articular Cartilage Constituents on Phosphotungstic Acid Enhanced Micro-Computed Tomography. PLoS ONE 12(1): e0171075. doi:10.1371/journal.pone.0171075

Effects of articular cartilage constituents on phosphotungstic acid enhanced micro-computed tomography

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Author: Karhula, Sakari S.1,2; Finnilä, Mikko A.1,3,4; Lammi, Mikko J.5,6;
Organizations: 1Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
2Infotech Doctoral Program, University of Oulu, Oulu, Finland
3Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
4Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
5Department of Integrative Medical Biology, University of Umeå, Umeå, Sweden
6School of Public Health, Health Science Center of Xi’an Jiaotong University, Key Laboratory of Trace Elements and Endemic Diseases, National Health and Family Planning Commission, Xi’an, P. R. China
7Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
8Mount Sinai Hospital, Toronto, Canada
9Department of Physics, University of Helsinki, Helsinki, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.7 MB)
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Language: English
Published: Public Library of Science, 2017
Publish Date: 2017-04-11


Contrast-enhanced micro-computed tomography (CEμCT) with phosphotungstic acid (PTA) has shown potential for detecting collagen distribution of articular cartilage. However, the selectivity of the PTA staining to articular cartilage constituents remains to be elucidated. The aim of this study was to investigate the dependence of PTA for the collagen content in bovine articular cartilage. Adjacent bovine articular cartilage samples were treated with chondroitinase ABC and collagenase to degrade the proteoglycan and the collagen constituents in articular cartilage, respectively. Enzymatically degraded samples were compared to the untreated samples using CEμCT and reference methods, such as Fourier-transform infrared imaging. Decrease in the X-ray attenuation of PTA in articular cartilage and collagen content was observed in cartilage depth of 0±13% and deeper in tissue after collagen degradation. Increase in the X-ray attenuation of PTA was observed in the cartilage depth of 13±39% after proteoglycan degradation. The X-ray attenuation of PTA-labelled articular cartilage in CEμCT is associated mainly with collagen content but the proteoglycans have a minor effect on the X-ray attenuation of the PTA-labelled articular cartilage. In conclusion, the PTA labeling provides a feasible CEμCT method for 3D characterization of articular cartilage.

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Series: PLoS one
ISSN: 1932-6203
ISSN-E: 1932-6203
ISSN-L: 1932-6203
Volume: 12
Issue: 1
Article number: e0171075
DOI: 10.1371/journal.pone.0171075
Type of Publication: A1 Journal article – refereed
Field of Science: 3126 Surgery, anesthesiology, intensive care, radiology
217 Medical engineering
Funding: This work was supported by: European Research Council (, grant no: 336267, SS; Suomen Akatemia (Academy of Finland,, grant no: 273571, SS; Suomen Akatemia (Academy of Finland,, grant no: 253579, HJN; Suomen Akatemia (Academy of Finland,, grant no: 268378, SS; Sigfrid Juselius Stiftelse (Sigfrid Juselius Foundation,, grant no: N/A, SS.
EU Grant Number: (336267) 3D-OA-HISTO - Development of 3D Histopathological Grading of Osteoarthritis
Academy of Finland Grant Number: 273571
Detailed Information: 273571 (Academy of Finland Funding decision)
253579 (Academy of Finland Funding decision)
268378 (Academy of Finland Funding decision)
Dataset Reference: All relevant data are within the paper and its Supporting Information file.
Copyright information: © 2017 Karhula et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.