Repair Mechanisms in Articular Cartilage—A Porcine in Vitro Study


Explants are excellent systems for studying homeostasis in cartilage. The systems are very useful in pharmacological studies involving OA-treatment and in studies of repair mechanisms during injury to hyaline cartilage. The purpose of this study was to evaluate the reparative processes occurring in a young age porcine cartilage explant model examining tissue by Light (LM) and Transmission Electron Microscopy (TEM). Explants of articular cartilage were dissected from the femoral condyles of immature one-year-old pigs and cultured in DMEM/F12 medium with FCS (stimulated explant) or in medium without FCS (control explant) for up to 4 weeks. After 1 - 4 weeks of culture with FCS, LM showed migration and proliferation of chondrocytes in cartilage close to the injured surface differentiating two areas: proliferative zone and necrotic zone. The chondrocytes present in the necrotic zone showed a polarization towards the injured surface. After budding through the injured surface, the chondrocytes formed repair tissue in an interface repair zone and in outer repair tissue. TEM showed chondrocytes in expanded lacunae involving the proliferative zone. The pericellular matrix of the expanded lacunae was partly dissolved, indicating release of matrix-degrading enzymes during proliferation and remodeling. Migratory chondrocytes were identified in oval lacunae close to the injured surface. The pericellular matrix of these oval lacunae was significantly dissolved and immunohistochemistry demonstrated strong staining with a polyclonale collagenase antibody around these units, suggesting release of matrix-degrad- ing collagenase contributing to chondrocyte mobility. We describe an explant model comprising two different repair systems in immature articular cartilage. This model provides us with new reference points that are important in understanding the repair mechanisms.

Share and Cite:

Skagen, P. , Kruse, H. and Horn, T. (2014) Repair Mechanisms in Articular Cartilage—A Porcine in Vitro Study. Microscopy Research, 2, 67-80. doi: 10.4236/mr.2014.24009.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Namba, R.S., Meuli, M., Sullivan, K.M., Le, A.X. and Adzick, N.S. (1998) Spontaneous Repair of Superficial Defects in Articular Cartilage in a Fetal Lamb Model. Journal of Bone and Joint Surgery, 80, 4-10.
[2] Wei, X., Gao, J. and Messner, K. (1997) Maturation-Dependent Repair of Untreated Osteochondral Defects in the Rabbit Knee Joint. Journal of Biomedical Materials Research, 34, 63-72.<63::AID-JBM9>3.0.CO;2-L
[3] Meachim, G. (1963) The Effect of Scarification on Articular Cartilage in the Rabbit. Journal of Bone and Joint Surgery, 45B, 150.
[4] Fuller, J.A. and Gadhially, F.N. (1972) Ultrastructural Observations on Surgically Produced Partial-Thickness Defects in Articular Cartilage. Clinical Orthopaedics, 86, 193-205.
[5] Gadhially, F.N., Thomas, I., Oryschak, A.F. and Lalonde, J.M. (1977) Long-Term Results of Superficial Defects in Articular Cartilage: A Scanning Electron-Microscopy Study. The Journal of Pathology, 121, 213.
[6] Cheung, H.S., Cottrell, W.H., Stephenson, K. and Nimni, M.E. (1978) In Vitro Collagen Biosynthesis in Healing and Normal Rabbit Articular Cartilage. Journal of Bone and Joint Surgery, 60A, 1076-1081.
[7] Kim, H.K.W., Moran, M.E. and Salter, R.B. (1991) The Potential for Regeneration of Articular Cartilage in Defects Created by Chondral Shaving and Subchondral Abrasion. Journal of Bone and Joint Surgery, 73A, 1301-1315.
[8] Landells, J.W. (1957) The Reactions of Injured Human Articular Cartilage. Journal of Bone and Joint Surgery, 39B, 548-562.
[9] Mankin, H.J. (1974) The Reaction of Articular Cartilage to Injury and Osteoarthritis, Part I. New England Journal of Medicine, 291, 1285-1292.
[10] Mankin, H.J. (1974) The Reaction of Articular Cartilage to Injury and Osteoarthritis, Part II. New England Journal of Medicine, 291, 1335-1340.
[11] Hunziker, E.B. and Rosenberg, L.C. (1996) Repair of Partial-Thickness Defects in Articular Cartilage: Cell Recruitment from the Synovial Membrane. The Journal of Bone and Joint Surgery, 78, 721-733.
[12] Verbruggen, G., Luyten, F.P. and Veys, E.M. (1985) Repair Function in Organ Cultured Human Cartilage. Replacement of Enzymatically Removed Proteoglycans during Long Term Organ Culture. The Journal of Rheumatology, 12, 665-674.
[13] Luyten, F.P., Verbruggen, G., Veys, E.M., Goffin, E. and De Pypere, H. (1987) In Vitro Repair Potential of Articular Cartilage: Proteoglycan Metabolism in the Different Areas of the Femoral Condyles in Human Cartilage Explants. The Journal of Rheumatology, 14, 329-334.
[14] Malemud, C.J., Shuckett, R. and Goldberg, V.M. (1988) Changes in Proteoglycans of Human Osteoarthritic Cartilage Maintained in Explant Culture: Implications for Understanding Repair in Osteoarthritis. Scandinavian Journal of Rheumatology—Supplement, 77, 7-12.
[15] Weiss, A., Livne, E., von der Mark, K., Heinegard, D. and Silbermann, M. (1998) Growth and Repair of Cartilage: Organ Culture System Utilizing Chondroprogenitor Cells of Condylar Cartilage in Newborn Mice. Journal of Bone and Mineral Research, 3, 93-100.
[16] Chen, A.C., Nagrampa, J.P., Schinagl, R.M., Lottman, L.M. and Sah, R.L. (1997) Chondrocyte Transplantation to Articular Cartilage Explants in Vitro. Journal of Orthopaedic Research, 15, 791-802.
[17] Quinn, T.M., Grodzinsky, A.J., Hunziker, E.B. and Sandy, J.D. (1998) Effects on Injurious Compression on Matrix Turnover around Individual Cells in Calf Articular Cartilage Explants. Journal of Orthopaedic Research, 16, 490-499.
[18] Quinn, T.M., Maung, A.A., Grodzinsky, A.J., Hunziker, E.B. and Sandy, J.D. (1999) Physical and Biological Regulation of Proteoglycan Turnover around Chondrocytes in Cartilage Explants. Implications for Tissue Degradation and Repair. Annals of the New York Academy of Sciences, 878, 420-441.
[19] Morales, T.I., Wahl, L.M. and Hascall, V.C. (1984) The Effects of Bacterial Lipopolysaccharides on the Biosynthesis and Release of Proteoglycans from Calf Articular Cartilage Cultures. Journal of Biological Chemistry, 259, 6720-6729.
[20] Tian, X.M., Chen, S.Q., Morales, T.I. and Hascall, V.C. (1989) Biochemical and Morphological Studies of Steady State and Lipopolysaccaride Treated Bovine Articular Cartilage Explant Cultures. Connective Tissue Research, 19, 195-218.
[21] Tew, S.R., Kwan, A.P.L., Hann, A., Thomson, B.M. and Archer, C.W. (2000) The Reactions of Articular Cartilage to Experimental Wounding. Arthritis & Rheumatism, 43, 215-225.<215::AID-ANR26>3.0.CO;2-X
[22] Tew, S., Redman, S., Kwan, A., Walker, E., Khan, I., Dowthwaite, G., Thomson, B. and Archer, C.W. (2001) Differences in Repair Responses between Immature and Mature Cartilage. Clinical Orthopaedics and Related Research, 391, 142-152.
[23] Key, A. (1931) Experimental Arthritis: The Changes in Joints Produced by Creating Defects in Articular Cartilage. Journal of Bone and Joint Surgery, 13, 725-739.
[24] Bennet, G.A., Bauer, W. and Maddock, S.J. (1932) A Study of the Repair of Articular Cartilage and the Reaction of Normal Joints of Adult Dogs to Surgically Created Defects of Articular Cartilage, “Joint Mice” and Patellar Displacement. The American Journal of Pathology, 8, 499-524.
[25] Redfern, P. (1969) On the Healing of Wounds in Articular Cartilage. Clinical Orthopaedics and Related Research, 64, 4-6.
[26] Calandruccio, R.A. and Gilmer, W.S. (1962) Proliferation, Regeneration and Repair of Articular Cartilage of Immature Animals. Journal of Bone and Joint Surgery, 44, 431-455.
[27] Mankin, H.J. (1962) Localisation of Tritiated Thymidine in Articular Cartilage of Rabbits. II. Repair in Immature Cartilage. Journal of Bone and Joint Surgery, 44, 688-698.
[28] Hembry, M., Dyce, J., Driesang, I., Hunziker, E.B., Fosang, A.J., Tyler, J.A. and Murphy, G. (2001) Immunolocalization of Matrix Metalloproteinases in Partial-Thickness Defects in Pig Articular Cartilage. The Journal of Bone and Joint Surgery, 83, 826-838.
[29] Shapiro, F., Koide, S. and Glimcher, M.J. (1993) Cell Origin and Differentiation in the Repair of Full-Thickness Defects of Articular Cartilage. The Journal of Bone and Joint Surgery, 75, 532-553.
[30] Mankin, H.J. and Lipiello, L. (1971) The Glycosaminoglycans of Normal and Arthritic Cartilage. Journal of Clinical Investigation, 50, 1712-1719.
[31] Nimni, M. and Deshmukh, K. (1973) Differences in Collagen Metabolism between Normal and Osteoarthritic Human Articular Cartilage. Science, 181, 751-752.
[32] Lee, D.A., Bently, G. and Archer, C.W. (1993) The Control of Cell Division in Articular Chondrocytes. Osteoarthritis Cartilage, 1, 137-146.
[33] Vincent, T., Hermansson, M., Bolton, M., Wait, R. and Saklatvala, J. (2002) Basic FGF Mediates an Immediate Response of Articular Cartilage to Mechanical Injury. Proceedings of the National Academy of Sciences of the United States, 99, 8259-8264.
[34] Stockwell, R.A. (1979) Biology of Cartilage Cells. Cambridge University Press, Cambridge.
[35] Redman, S.N., Dowthwaite, G.P., Thomson, B.M. and Archer, C.W. (2004) The Cellular Responses of Articular Cartilage to Sharp and Blunt Trauma. Osteoarthritis Cart, 12, 106-116.
[36] Malemud, C.J., Papay, R.S., Hering, T.M., Holderbaum, D., Goldberg, V.M. and Haqqi, T.M. (1995) Phenotypic Modulation of Newly Synthesized Proteoglycans in Human Cartilage and Chondrocytes. Osteoarthritis Cart, 3, 227- 238.
[37] Tanaka, H., Nagai, E., Murata, H., Tsubone, T., Shirakura, Y., Sugiyama, T., Taguchi, T. and Kawai, S. (2001) Involvement of Bone Morphogenic Protein-2 (BMP) in the Pathological Ossification Process of the Spinal Ligament. Rheumatology, 40, 1163-1168.
[38] Takebayashi, T., Iwamoto, M., Jikko, A., Matsumura, T., Enomoto-Iwamoto, M., Myoukai, F., Koyama, E., Yamaai, T., Matsumoto, K., Nakamura, T., et al. (1995) Hepatocyte Growth Factor (Scatter Factor) Modulates Cell Motility, Proliferation and Proteoglycan Synthesis of Chondrocytes. The Journal of Cell Biology, 129, 1411-1419.
[39] Shimizu, M., Minakuchi, K., Kaji, S. and Koga, J. (1997) Chondrocyte Migration to Fibronectin, Type I Collagen and Type II Collagen. Cell Structure and Function, 22, 309-315.
[40] Maniwa, S., Ochi, M., Motomura, T., Nishikori, T., Chen, J. and Naora, H. (2001) Effects of Hyaluronic Acid and Basic Fibroblast Growth Factor on Motility of Chondrocytes and Synovial Cells in Culture. Acta Orthopaedica Scandinavica, 72, 299-303.
[41] Wei, Q., Murray, M.M., Shortkroff, S., Lee, C.R., Martin, S.D. and Spector, M. (2000) Outgrowth of Chondrocytes from Human Articular Cartilage Explants and Expression of Smooth Muscle Actin. Wound Repair and Regeneration, 8, 383-391.
[42] Billinghurst, R.C., Wu, W., Ioncscu, M., Reiner, A., Dahlberg, L. and Chen, J. (2000) Comparison of the Degradation of Type II Collagen and Proteoglycan in Nasal and Articular Cartilages Induced by Interleukin-1 and the Selective Inhibition of Type II Collagen Cleavage by Collagenase. Arthritis Rheum, 43, 664-672.<664::AID-ANR24>3.0.CO;2-D
[43] Dahlberg, L., Billinghurst, C., Manner, P., Ionescu, M., Reiner, A., Tanzer, M., et al. (2000) Selective Enhancement of Collagenase-Mediated Cleavage of Resident Type II Collagen in Cultured Osteoarthritic Cartilage and Arrest with a Synthetic Inhibitor That Spares Collagenase 1 (Matrix Metalloproteinase 1). Arthritis & Rheumatism, 43, 673-682.<673::AID-ANR25>3.0.CO;2-8
[44] Stremme, S., Duerr, S., Bau, B., Schmid, E. and Aigner, T. (2003) MMP-8 Is Only a Minor Gene Product of Human Adult Articular Chondrocytes of the Knee. Clinical and Experimental Rheumatology, 21, 205-209.
[45] Knauper, V., Lopez-Otin, C., Smith, B., Knight, G. and Murphy, G. (1996) Biochemical Characterization of Human Collagenase-3. Journal of Biological Chemistry, 271, 1544-1550.
[46] Billinghurst, R.C., Dahlberg, L., Ionescu, M., Reiner, A., Bourne, R., Rorabeck, C., Mitchell, P., Hambor, J., Diekmann, O., Tscheche, H., Chen, J., Van Wart, H. and Poole, A.R. (1997) Enhanced Cleavage of Type II Collagen by Collagenases in Osteoarthritic Articular Cartilage. Journal of Clinical Investigation, 99, 1534-1545.
[47] Miller, E.J., Harris Jr., E.D. Chung, E., Finch Jr., J.E., McCroskery, P.A. and Butler, W.T. (1976) Cleavage of Type II and III Collagens with Mammalian Collagenase: Site of Cleavage and Primary Structure at the NH2-Terminal Portion of the Smaller Fragment Released from Both Collagens. Biochemistry, 15, 787-792.
[48] Mitchell, P.G., Magna, H.A., Reeves, L.M., Lopresti-Morrow, L.L., Yocum, S.A., Rosner, P.J., Geoghegan, K.F. and Hambor, J.E. (1996) Cloning, Expression and Type II Collagenolytic Activity of Matrix Metalloproteinase-13 from Human Osteoarthritic Cartilage. Journal of Clinical Investigation, 97, 761-768.
[49] Freemont, A.J., Byers, R.J., Taiwo, Y.O. and Hoyland, J.A. (1999) In Situ Zymographic Localisation of Type II Collagen Degrading Activity in Osteoarthritic Human Articular Cartilage. Annals of the Rheumatic Diseases, 58, 357-365.
[50] Alevizopoulos, A. and Mermod, N. (1997) Transforming Growth Factor-Beta: The Breaking Open of a Black Box. BioEssays, 19, 581-591.
[51] Ornitz, D.M. and Leder, P. (1992) Ligand Specificity and Heparin Dependence of Fibroblast Growth Factor Receptors 1 and 3. Journal of Biological Chemistry, 267, 16305-16311.
[52] Reindel, E.S., Ayroso, A.M., Chen, A.C., Chun, D.M., Schinagl, R.M. and Sah, R.L. (1995) Integrative Repair of Articular Cartilage in Vitro: Adhesive Strength of the Interface Region. Journal of Orthopaedic Research, 13, 751-760.
[53] Hunziker, E.B. and Schenk, R.K. (1984) Cartilage Ultrastructure after High Pressure Freezing, Freeze Substitution and Low Temperature Embedding. II. Intercellular Matrix Ultrastructure—Preservation of Proteoglycans in Their Native State. The Journal of Cell Biology, 1, 277-282.
[54] Hay, E.D. (1981) Collagen and Embryonic Development. In: Hay, E.D., Ed., Cell Biology of Extracellular Matrix, Plenum, New York, 379-409.

Copyright © 2023 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.