title: Effects of Articular Cartilage Constituents on Phosphotungstic Acid Enhanced Micro-Computed Tomography.
abstract: 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.
authors.affiliation: Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.|Infotech Doctoral Program, University of Oulu, Oulu, Finland.
authors.forename: Sakari S
authors.initials: SS
authors.lastname: Karhula
authors.affiliation: Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.|Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.|Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
authors.forename: Mikko A
authors.initials: MA
authors.lastname: Finnilä
authors.affiliation: Department of Integrative Medical Biology, University of Umeå, Umeå, Sweden.|School 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.
authors.forename: Mikko J
authors.initials: MJ
authors.lastname: Lammi
authors.affiliation: Department of Integrative Medical Biology, University of Umeå, Umeå, Sweden.
authors.forename: Janne H
authors.initials: JH
authors.lastname: Ylärinne
authors.affiliation: Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.
authors.forename: Sami
authors.initials: S
authors.lastname: Kauppinen
authors.affiliation: Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.|Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
authors.forename: Lassi
authors.initials: L
authors.lastname: Rieppo
authors.affiliation: Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.|Mount Sinai Hospital, Toronto, Canada.
authors.forename: Kenneth P H
authors.initials: KP
authors.lastname: Pritzker
authors.affiliation: Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.|Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.|Department of Physics, University of Helsinki, Helsinki, Finland.
authors.forename: Heikki J
authors.initials: HJ
authors.lastname: Nieminen
authors.affiliation: Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.|Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.|Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.
authors.forename: Simo
authors.initials: S
authors.lastname: Saarakkala
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000378:metabolism*; D002417:Cattle; D019765:Chondroitin ABC Lyase / Q000378:metabolism; D017364:Collagenases / Q000378:metabolism; D004587:Electrophoresis, Agar Gel; D007485:Ioxaglic Acid / Q000737:chemistry; D010772:Phosphotungstic Acid / Q000737:chemistry*; D011509:Proteoglycans / Q000378:metabolism; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D011509:Proteoglycans; D010772:Phosphotungstic Acid; D017364:Collagenases; D019765:Chondroitin ABC Lyase; D007485:Ioxaglic Acid