Tissue Engineering of the Intervertebral Disc with Cultured Nucleus Pulposus Cells Using Atelocollagen Scaffold and Gene Therapy

ABSTRACT

STUDY DESIGN: This is an in-vitro experiment using rabbit intervertebral disc (IVD) cells and growth factors. OBJECTIVES: We wanted to determine the effect of types I, and II atelocollagen and growth factor gene therapy for matrix regeneration of rabbit IVD cells. SUMMARY OF THE LITERATURE REVIEW Adenovirus-medicated growth factor gene therapy is efficient for matrix regeneration of the IVD. Atellocollagen has provided a favorable environment for matrix synthesis. However, a combined approach using gene and cell therapy in an atelocollagen scaffold has not yet been attempted. MATERIALS AND METHODS: Rabbit IVD cells were transduced with Ad/TGF-beta1 and Ad/BMP-2. The cells were then implanted to the atelocollagen scaffold. The [methyl-3H]thymidine incorporation for DNA synthesis and the [35S]sulfur incorporation for proteoglycan synthesis were measured. RT-PCR was performed for assessing the aggrecan, collagen type I, collagen type II and osteocalcin mRNA expressions. RESULTS: The rabbit IVD cells with Ad/TGF-beta1 and that were cultured in type I atelocollagen showed a 130% increase in new proteoglycan synthesis, while the rabbit IVD cells with Ad/TGF-beta1 and that were cultured in type II atelocollagen showed a 180% increase in new proteoglycan synthesis (p<0.05). The rabbit IVD cells with Ad/BMP-2 and that were cultured in type I atelocollagen showed a 70% increase in new proteoglycan synthesis, while the rabbit IVD cells with Ad/BMP-2 and that were cultured in type II atelocollagen showed a 95% increase (p<0.05). Rabbit IVD cells with Ad/TGF-beta1 and Ad/BMP-2 and that were cultured in type I and II atelocollagen demonstrated increased collagen type I and II mRNA expressions without an osteocalcin mRNA expression (p<0.05). CONCLUSION: Cell and gene therapy in an atelocollagen scaffold provided a efficient mechanism for chondrogenic matrix regeneration of rabbit IVD cells.