Early in situ changes in chondrocyte biomechanical responses due to a partial meniscectomy in the lateral compartment of the mature rabbit knee joint.
We determined the biomechanical responses of chondrocytes to indentation at specific locations within the superficial zone of cartilage (i.e. patellar, femoral groove, femoral condylar and tibial plateau sites) taken from female New Zealand white rabbits three days after a partial meniscectomy in the lateral compartment of a knee joint. Confocal laser scanning microscopy combined with a custom indentation system was utilized to image chondrocyte responses at sites taken from ten contralateral and experimental knee joints. Cell volume, height, width and depth changes, global, local axial and transverse strains and Young׳s moduli were determined. Histological assessment was performed and proteoglycan content from the superficial zone of each site was determined. Relative to contralateral group cells, patellar, femoral groove and lateral femoral condyle cells in the experimental group underwent greater volume decreases (p < 0.05), due to smaller lateral expansions (with greater decreases in cell height only for the lateral femoral condyle cells; p < 0.05) whereas medial femoral and medial tibial plateau cells underwent smaller volume decreases (p < 0.05), due to less deformation in cell height (p < 0.05). Proteoglycan content was reduced in the patellar (p > 0.05), femoral groove, medial femoral condyle and medial tibial plateau experimental sites (p < 0.05). The findings suggest: (i) cell biomechanical responses to cartilage loading in the rabbit knee joint can become altered as early as 3 days after a partial meniscectomy, (ii) are site-specific, and (iii) occur before alterations in tissue mechanics or changes detectable with histology.
Department of Applied Physics, University of Eastern Finland, Kuopio, Finland. Electronic address: jfickbiomaterials@yahoo.com.
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JM
Fick
Department of Applied Physics, University of Eastern Finland, Kuopio, Finland. Electronic address: ari.p.ronkainen@uef.fi.
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A
P Ronkainen
Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. Electronic address: rmjmadde@ucalgary.ca.
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R
Madden
Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. Electronic address: ajsawats@ucalgary.ca.
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A
Sawatsky
Institute of Biomedicine, Anatomy, University of Eastern Finland, Kuopio FI-70211, Finland. Electronic address: virpi.tiitu@uef.fi.
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Tiitu
Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. Electronic address: wherzog@ucalgary.ca.
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Herzog
Department of Applied Physics, University of Eastern Finland, Kuopio, Finland. Electronic address: rami.korhonen@uef.fi.
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RK
Korhonen
D000818:Animals; D048429:Cell Size; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D005260:Female; D007719:Knee Joint / Q000166:cytology* / Q000000981:diagnostic imaging / Q000502:physiology; D055595:Mechanical Phenomena; D000072600:Meniscus / Q000601:surgery*; D011509:Proteoglycans / Q000378:metabolism; D011817:Rabbits
D011509:Proteoglycans
Articular cartilage; Chondrocyte biomechanical responses; Deformation; In situ; Mature rabbit knee joint; Osteoarthritis; Partial meniscectomy