Co-culture of osteochondral explants and synovial membrane as in vitro model for osteoarthritis

• Published in: PloS one 2019-04, Vol.14 (4), p.e0214709-e0214709
• Main Authors: Haltmayer, Eva, Ribitsch, Iris, Gabner, Simone, Rosser, Julie, Gueltekin, Sinan, Peham, Johannes, Giese, Ulrich, Dolezal, Marlies, Egerbacher, Monika, Jenner, Florien
• Format: Article
• Language: English
• Subjects: ADAM protein; Aggrecan; Animals; Arthritis; Biocompatibility; Biology and Life Sciences; Biomedical materials; Care and treatment; Cartilage; Cartilage diseases; Cell adhesion & migration; Chemical damage; Chondrocytes - cytology; Chondrocytes - metabolism; Chondrocytes - pathology; Coculture Techniques; Collagen; Collagen Type I - genetics; Collagen Type I - metabolism; Collagenase 3; Cytokines; Development and progression; Disease; EDTA; Embryology; Enzyme-linked immunosorbent assay; Explants; Extracellular matrix; Gene expression; Genes; Histology; Horses; Hospitals; IL-1β; Immunohistochemistry; Inflammation; Inflammatory response; Interleukin 1; Interleukin 6; Interleukin-1beta - pharmacology; Interleukin-6 - genetics; Interleukins; Macrophages; Matrix metalloproteinase; Matrix Metalloproteinase 1 - genetics; Matrix Metalloproteinase 1 - metabolism; Medicine and Health Sciences; Models, Biological; Necrosis; Nitric oxide; Nitric Oxide - metabolism; Organic chemistry; Osteoarthritis; Osteoarthritis - pathology; Osteochondritis; Phenotypes; Research and Analysis Methods; Rheumatism; Risk factors; Statistical analysis; Stromelysin 1; Surgery; Synovial membrane; Synovial Membrane - cytology; Synovial Membrane - metabolism; Thickness; Thrombospondin; Tissue engineering; Tumor necrosis factor; Tumor Necrosis Factor-alpha - pharmacology; Tumor necrosis factor-α; Tumors; Urea; Urea - metabolism; Ureas; Veterinary medicine
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0214709

The purpose of the current study was to establish an in vitro model for osteoarthritis (OA) by co-culture of osteochondral and synovial membrane explants. Osteochondral explants were cultured alone (control-1) or in co-culture with synovial membrane explants (control-2) in standard culture medium or with interleukin-1β (IL1β) and tumor necrosis factor (TNFα) added to the culture medium (OA-model-1 = osteochondral explant; OA-model-2 = osteochondroal-synovial explant). In addition, in OA-model groups a 2-mm partial-thickness defect was created in the centre of the cartilage explant. Changes in the expression of extracellular matrix (ECM) genes (collagen type-1 (Col1), Col2, Col10 and aggrecan) as well as presence and quantity of inflammatory marker genes (IL6, matrix metalloproteinase-1 (MMP1), MMP3, MMP13, a disintegrin and metalloproteinase with-thrombospondin-motif-5 (ADAMTS5) were analysed by immunohistochemistry, qPCR and ELISA. To monitor the activity of classically-activated pro-inflammatory (M1) versus alternatively-activated anti-inflammatory/repair (M2) synovial macrophages, the nitric oxide/urea ratio in the supernatant of osteochondral-synovial explant co-cultures was determined. In both OA-model groups immunohistochemistry and qPCR showed a significantly increased expression of MMPs and IL6 compared to their respective control group. ELISA results confirmed a statistically significant increase in MMP1and MMP3 production over the culturing period. In the osteochondral-synovial explant co-culture OA-model the nitric oxide/urea ratio was increased compared to the control group, indicating a shift toward M1 synovial macrophages. In summary, chemical damage (TNFα, IL1β) in combination with a partial-thickness cartilage defect elicits an inflammatory response similar to naturally occurring OA in osteochondral explants with and without osteochondral-synovial explant co-cultures and OA-model-2 showing a closer approximation of OA due to the additional shift of synovial macrophages toward the pro-inflammatory M1 phenotype.