University of Oulu

Rieppo L, Janssen L, Rahunen K, Lehenkari P, Finnilä MAJ, Saarakkala S (2019) Histochemical quantification of collagen content in articular cartilage. PLoS ONE 14(11): e0224839.

Histochemical quantification of collagen content in articular cartilage

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Author: Rieppo, Lassi1; Janssen, Lauriane1,2; Rahunen, Krista1;
Organizations: 1Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
2Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, Oulu, Finland
3Department of Surgery and Intensive Care, Oulu University Hospital, Oulu, Finland
4Cancer and Translational Medicine Research Unit, Faculty of Medicine, University of Oulu, Oulu, Finland
5Infotech Oulu, University of Oulu, Oulu, Finland
6Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.7 MB)
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Language: English
Published: Public Library of Science, 2019
Publish Date: 2020-03-26


Background: Articular cartilage (AC) is mainly composed of water, type II collagen, proteoglycans (PGs) and chondrocytes. The amount of PGs in AC is routinely quantified with digital densitometry (DD) from Safranin O-stained sections, but it is unclear whether similar method could be used for collagens.

Objective: The aim of this study was to clarify whether collagens can be quantified from histological AC sections using DD.

Material and methods: Sixteen human AC samples were stained with Masson’s trichrome or Picrosirius red. Optical densities of histological stains were compared to two commonly used collagen parameters (amide I and collagen CH2 side chain peak at 1338cm-1) measured using Fourier Transform Infrared (FTIR) spectroscopic imaging.

Results: Optical density of Modified Masson’s trichrome staining, which included enzymatic removal of PGs before staining, correlated significantly with FTIR-derived collagen parameters at almost all depths of cartilage. The other studied staining protocols displayed significant correlations with the reference parameters at only few depth layers.

Conclusions: Based on our findings, modified Masson’s trichrome staining protocol is suitable for quantification of AC collagen content. Enzymatic removal of PGs prior to staining is critical as us allows better staining of the collagen. Further optimization of staining protocols may improve the results in the future studies.

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Series: PLoS one
ISSN: 1932-6203
ISSN-E: 1932-6203
ISSN-L: 1932-6203
Volume: 14
Issue: 11
Article number: e0224839
DOI: 10.1371/journal.pone.0224839
Type of Publication: A1 Journal article – refereed
Field of Science: 217 Medical engineering
318 Medical biotechnology
1182 Biochemistry, cell and molecular biology
Funding: The financial support from the Academy of Finland grant no. 310466 (LR), Academy of Finland grants no. 268378 and 273571 (SS), Sigrid Juselius Foundation (SS), European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement no. 336267 (SS), and the strategic funding of the University of Oulu is acknowledged. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
EU Grant Number: (336267) 3D-OA-HISTO - Development of 3D Histopathological Grading of Osteoarthritis
Academy of Finland Grant Number: 310466
Detailed Information: 310466 (Academy of Finland Funding decision)
268378 (Academy of Finland Funding decision)
273571 (Academy of Finland Funding decision)
Copyright information: © 2019 Rieppo 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.