Abstract
The research utilizes gelatin—a degradated product of collagen as scaffolds for cartilage tissue engineering in vitro. Gelatin is a kind of natural polymers, it has advantage of very good biocompatibility and biodegradation property; besides, it’s degradation molecular would hardly induce inflammation and immunization reaction inside bodies. These benefits make it suitable for the adherence, proliferation and synthesizing ECM of cartilage cells. But due to its weak mechanical properties, we use natural cross-linking reagent---genipin which was extracted from Gardeniae to make gelatin more stable, and elongate its degradation time in the medium or even in the body, to make it more suitable for chondrocyte culturing. From our lab’s previous study, we know that gelatin is an excellent material for cartilage culture. Hence I further altered the temperature of cross-linking reactions and adjusted the processes of lyophilization, to produce scaffolds with four ranges of different pore size. To investigate whether different pore sizes influence proliferation and differentiation of cartilage cells, articular chondrocytes of Wistar rats within 7 days of birth were transplanted into the scaffolds. DNA assay, GAG assay, H&E staining, Safranin-O staining and RT-PCR were used to analyze the behavior of chondrocytes. We found that cell’s metabolism could be affected by the configuration of the scaffold. The secretion of ECM of cells in the scaffolds with largest inner pores has the most significant amount over the other groups. We also found that cells in the smallest pores of scaffolds often show a de-differentiation form, because of lacking space in scaffolds. The phenotype of the cells will be maintained easily through the progressive increment of the pore size in scaffolds. In conclusion, cells prefer a pore size between 250μm to 500μm to produce ECM and proliferate, and the size of the space is the key factor for cell’s metabolism. On the other hand, the mechanical tests showed that our scaffolds have a good resilience. After 30 days culture, the scafflds’ anti-compression capability have made a great progress in the group with the largest inner pores. These facts have proven that gelatin scaffold is a very suitable material for cartilage tissue engineering.