Meniscal biomechanical alterations in an ACLT rabbit model of early osteoarthritis.
OBJECTIVE
The purpose of this study was to analyze the early biomechanical alterations of menisci during the early stage of osteoarthritis (OA) development and to correlate them with the chemical composition and matrix alteration. A particular focus was paid to pathological changes in glycosaminoglycan (GAG) content and collagen fiber architecture.


METHODS
Menisci (n = 24) were removed from rabbits' knee joints 6 weeks following surgical anterior cruciate ligament transection (ACLT). Both the anterior and posterior regions of medial and lateral menisci were characterized using indentation tests, Raman microspectroscopy (RM), biphotonic confocal microscopy (BCM) and histology.


RESULTS
Mechanical and matrix alterations occurred in both regions of medial and lateral menisci. A significant decrease in the mechanical properties was observed in OA menisci, with a mean reduced modulus from 2.3 to 1.1 MPa. Microstructural observations revealed less organized and less compact collagen bundles in operated menisci than in contralateral menisci, as well as a loss of fiber tension. GAG content was increased in OA menisci, especially in the damaged areas. Neither changes in the secondary structure of collagen nor mineralization were detected through RM at this stage of OA.


CONCLUSIONS
ACLT led to a disorganization of the collagen framework at the early stage of OA development, which decreases the mechanical resistance of the menisci. GAG content increases in response to this degradation. All of these results demonstrate the strong correlation between matrix and mechanical alterations.
LTDS, UMR CNRS 5513, Université de Lyon, Ecole centrale de Lyon, 36 av Guy de Collongue, 69134 Ecully Cedex, France.
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Levillain
Research Unit ICE, UPSP 2011.03.101, Université de Lyon, Veterinary Campus of VetAgro Sup, 69 280 Marcy l'Etoile, France.
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Boulocher
School of Pharmaceutical Sciences, University of Geneva and Lausanne, Quai Ernest-Ansermet 30, 1211 Geneva, Switzerland.
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Kaderli
Research Unit ICE, UPSP 2011.03.101, Université de Lyon, Veterinary Campus of VetAgro Sup, 69 280 Marcy l'Etoile, France.
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Viguier
B2OA, UMR CNRS 7052 CHU Lariboisière Saint Louis, 10 av de Verdun, 75020 Paris France.
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Hannouche
LTDS, UMR CNRS 5513, Université de Lyon, Ecole centrale de Lyon, 36 av Guy de Collongue, 69134 Ecully Cedex, France. Electronic address: thierry.hoc@ec-lyon.fr.
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Hoc
LTDS, UMR CNRS 5513, Université de Lyon, Ecole centrale de Lyon, 36 av Guy de Collongue, 69134 Ecully Cedex, France.
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Magoariec
D000818:Animals; D000070598:Anterior Cruciate Ligament Injuries; D001169:Arthritis, Experimental / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D003094:Collagen / Q000648:ultrastructure; D006025:Glycosaminoglycans / Q000378:metabolism; D008297:Male; D008592:Menisci, Tibial / Q000378:metabolism / Q000503:physiopathology*; D018613:Microscopy, Confocal; D020370:Osteoarthritis, Knee / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D011817:Rabbits; D013314:Stress, Mechanical
D006025:Glycosaminoglycans; D003094:Collagen
Collagen; Glycosaminoglycan; Indentation; Meniscus; Osteoarthritis