University of Oulu

Mustonen, A., Käkelä, R., Finnilä, M.A.J. et al. Anterior cruciate ligament transection alters the n-3/n-6 fatty acid balance in the lapine infrapatellar fat pad. Lipids Health Dis 18, 67 (2019).

Anterior cruciate ligament transection alters the n-3/n-6 fatty acid balance in the lapine infrapatellar fat pad

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Author: Mustonen, Anne-Mari1,2; Käkelä, Reijo3,4; Finnilä, Mikko A. J.5,6,7;
Organizations: 1Institute of Biomedicine/Anatomy, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
2Department of Environmental and Biological Sciences, Faculty of Science and Forestry, University of Eastern Finland, Joensuu, Finland
3Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
4Helsinki University Lipidomics Unit (HiLIPID), Helsinki Institute for Life Science (HiLIFE), University of Helsinki, Helsinki, Finland
5Department of Applied Physics, Faculty of Science and Forestry, University of Eastern Finland, Kuopio, Finland
6Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland
7Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
8Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
9Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.8 MB)
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Language: English
Published: Springer Nature, 2019
Publish Date: 2020-04-27


Background: The infrapatellar fat pad (IFP) of the knee joint has received lots of attention recently due to its emerging role in the pathogenesis of osteoarthritis (OA), where it displays an inflammatory phenotype. The aim of the present study was to examine the infrapatellar fatty acid (FA) composition in a rabbit (Oryctolagus cuniculus) model of early OA created by anterior cruciate ligament transection (ACLT).

Methods: OA was induced randomly in the left or right knee joint of skeletally mature New Zealand White rabbits by ACLT, while the contralateral knee was left intact. A separate group of unoperated rabbits served as controls. The IFP of the ACLT, contralateral, and control knees were harvested following euthanasia 2 or 8 weeks post-ACLT and their FA composition was determined with gas chromatography–mass spectrometry.

Results: The n-3/n-6 polyunsaturated FA (PUFA) ratio shifted in a pro-inflammatory direction after ACLT, already observed 2 weeks after the operation (0.20 ± 0.008 vs. 0.18 ± 0.009). At 8 weeks, the FA profile of the ACLT group was characterized with increased percentages of 20:4n-6 (0.44 ± 0.064 vs. 0.98 ± 0.339 mol-%) and 22:6n-3 (0.03 ± 0.014 vs. 0.07 ± 0.015 mol-%) and with decreased monounsaturated FA (MUFA) sums (37.19 ± 1.586 vs. 33.20 ± 1.068 mol-%) and n-3/n-6 PUFA ratios (0.20 ± 0.008 vs. 0.17 ± 0.008). The FA signature of the contralateral knees resembled that of the unoperated controls in most aspects, but had increased proportions of total n-3 PUFA and reduced MUFA sums.

Conclusions: These findings provide novel information on the effects of early OA on the infrapatellar FA profile in the rabbit ACLT model. The reduction in the n-3/n-6 PUFA ratio of the IFP is in concordance with the inflammation and cartilage degradation in early OA and could contribute to disease pathogenesis.

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Series: Lipids in health and disease
ISSN: 1476-511X
ISSN-E: 1476-511X
ISSN-L: 1476-511X
Volume: 18
Issue: 1
Article number: 67
DOI: 10.1186/s12944-019-1008-5
Type of Publication: A1 Journal article – refereed
Field of Science: 3111 Biomedicine
Funding: The work was financially supported by the Academy of Finland (grant no 286526 to RKK, grant no 303786 to SS), Sigrid Jusélius Foundation (RKK), European Research Council under the European Union's Seventh Framework Programme (FP/2007–2013) (ERC grant agreement no 336267 to SS), Canadian Institutes of Health Research (AS, WH), Canada Research Chairs Program (WH), Killam Foundation (WH), University of Eastern Finland (MAJF), Finnish Cultural Foundation (MAJF), and Jane and Aatos Erkko Foundation (A-MM). 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: 303786
Detailed Information: 303786 (Academy of Finland Funding decision)
Copyright information: © The Author(s). 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.