engleski

Preclinical animal model - novel technology for articular cartilage repair

Usual clinical practice for autologous chondrocyte implantation (ACI) involves harvesting of articular cartilage from non- weightbearing part of the joint. Although effective, it induces additional trauma to the joint and additional surgical procedure with anesthesia. Alternative source of chondrocytes would substantially decrease morbidity and duration of the procedure, as well as the cost of the procedure. Nasal chondrocytes could be viable alternative for ACI in human patients. Before using it in clinical settings, it is necessary to test this hypothesis on translational (large animal) model. Designed model was chronic, full-thickness cartilage defect placed on lateral and medial femoral condyles in sheep. The protocol included two surgical procedures. First procedure was to create two partial-thickness defects, 4 mm in diameter on the lateral and medial femoral condyle with a standard mosaicplasty instruments used in human orthopaedic surgery. Biopsy of nasal septum cartilage was also performed with skin biopsy puncher, 8 mm in diameter. Cartilage samples from both origins were used for production of autologous tissue grafts. Chondrocytes were isolated, seeded on biphasic collagen-hydroxiapatite scaffolds, and cultured in automated bioreactor for 5 weeks. Engineered tissue was then implanted in condyle defects during second procedure. First, 4 mm partial-thickness defects were converted to osteochondral defects 6, 5 mm in diameter and 5 mm deep. Then engineered cartilage tissue was implanted. There were four study groups. Autologous tissue grafts, engineered from scaffold and nasal septum chondrocytes were implanted in the experimental group of animals. One group was implanted with autologous tissue grafts engineered from scaffold and articular chondrocytes. In one group cell free scaffolds were implanted while last group served as negative control in which only conversion of defect was performed, but it was left untreated. Animals were sacrificed and tissue analysis was performed at three different time points: 6 weeks, 3 months and 12 months after the implantation. Tissue analysis included macroscopic, microscopic and molecular evaluation. ICRS score was used to evaluate macroscopic apperance of the repair tissue. Microscopic analysis included different stains (hematoxylin-eosin, safranin O, picrosirius) and immunohistochemistry (collagen I, II and aggrecan) to determine the type of repair tissue, organization of collagen and integration. Semi-quantitative data of morphology were obtained with histological score ICRS II. ELISA and DMMB assays were performed to quantify the amount of collagen I, II and glycosaminoglycans in repair tissue. Results confirmed the feasibility of production of autologous cartilage tissue grafts from nasal septum chondrocyte for treatment of condyle cartilage defects. Furthermore, nasal chondrocyte grafts showed promising results in restoration of damaged articular cartilage. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n°278807.

translational animal model ; sheep ; cartilage repair

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