Tissue engineered cartilage on collagen and PHBV matrices

Cartilage engineering is a very novel approach to tissue repair through use of implants. Matrices of collagen containing calcium phosphate (CaP–Gelfix®), and matrices of poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) were produced to create a cartilage via tissue engineering. The matrices were characterized by scanning electron microscopy (SEM) and electron diffraction spectroscopy (EDS). Porosity and void volume analysis were carried out to characterize the matrices. Chondrocytes were isolated from the proximal humerus of 22 week-old male, adult, local albino rabbits. For cell type characterization, Type II collagen was measured by Western Blot analysis. The foams were seeded with 1×106 chondrocytes and histological examinations were carried out to assess cell–matrix interaction. Macroscopic examination showed that PHBV (with or without chondrocytes) maintained its integrity for 21 days, while CaP–Gelfix® was deformed and degraded within 15 days. Cell-containing and cell-free matrices were implanted into full thickness cartilage defects (4.5 mm in diameter and 4 mm in depth) at the patellar groove on the right and left knees of eight rabbits, respectively. In vivo results at 8 and 20 weeks with chondrocyte seeded PHBV matrices presented early cartilage formation resembling normal articular cartilage and revealed minimal foreign body reaction. In CaP–Gelfix® matrices, fibrocartilage formation and bone invasion was noted in 20 weeks. Cells maintained their phenotype in both matrices. PHBV had better healing response than CaP–Gelfix®. Both matrices were effective in cartilage regeneration. These matrices have great potential for use in the repair of joint cartilage defects.