Type I collagen scaffold with WNT5A plasmid for in situ cartilage tissue engineering

BACKGROUND: Cartilage tissue lacks the ability to heal. Cartilage tissue engineering using cell-free scaffolds has been increasingly used in recent years. OBJECTIVE: This study describes the use of a type I collagen scaffold combined with WNT5A plasmid to promote chondrocyte proliferation and differentiation in a rabbit osteochondral defect model. METHODS: Type I collagen was extracted and fabricated into a collagen scaffold. To improve gene transfection efficiency, a cationic chitosan derivative N,N,N-trimethyl chitosan chloride (TMC) vector was used. A solution of TMC/WNT5A complexes was adsorbed to the collagen scaffold to prepare a WNT5A scaffold. Osteochondral defects were created in the femoral condyles of rabbits. The rabbits were divided into defect, scaffold, and scaffold with WNT5A groups. At 6 and 12 weeks after creation of the osteochondral defects, samples were collected from all groups for macroscopic observation and gene expression analysis. RESULTS: Samples from the defect group exhibited incomplete cartilage repair, while those from the scaffold and scaffold with WNT5A groups exhibited "preliminary cartilage" covering the defect. Cartilage regeneration was superior in the scaffold with WNT5A group compared to the scaffold group. Safranin O staining revealed more proteoglycans in the scaffold and scaffold with WNT5A groups compared to the defect group. The expression levels of aggrecan, collagen type II, and SOX9 genes were significantly higher in the scaffold with WNT5A group compared to the other two groups. CONCLUSIONS: Type I collagen scaffold showed effective adsorption and guided the three-dimensional arrangement of stem cells. WNT5A plasmid promoted cartilage repair by stimulating the expression of aggrecan, type II collagen, and SOX9 genes and proteins, as well as inhibiting cartilage hypertrophy.