Cartilage tissue engineering on three dimensional scaffolds using human tooth germ stem cells

Cartilage tissue engineering strategies are mainly focused on repairing or regenerating a diseased or damaged joint cartilage tissue through the design and use of cell-containing biodegradable biomaterials. Dental stem cells obtained from tooth germs of human third molars (wisdom teeth) were shown to be a significant cell source since they do not differentiate until the age of five - six. Besides, these cells were proven to be capable of chondrogenic differentiation. As a scaffold material, PCL and PLLA are two of the most frequently used biomaterials in cartilage tissue engineering applications due to their high biocompatibilities and processabilities.The main objective of this study was to induce cartilage regeneration through differentiation of HTGSCs into chondrocytes on different 3-D scaffolds. For that purpose, PCL, PLLA, and PCL:PLLA (50:50) scaffolds were prepared by salt leaching technique. First, scaffold topographies were studied by scanning electron microscopy. Then, HTGSCs isolated from impacted third molar tooth germs of young adult patients were grown on the scaffolds in the chondrogenic differentiation media for 3 weeks. Cell proliferation on the scaffolds was quantified by MTS assay. Immunostaining was carried out for morphological and differentiation analyses. Real Time PCR was performed to determine the expression levels of cartilage-specific genes.Immunohistochemistry analyses revealed that the cells attached onto the scaffolds and deposited cartilage-specific ECM. As shown by MTS assay, all of the scaffolds supported cell proliferation. After 21 days of incubation in cartilage differentiation media, expression of collagen type II was increased in all cells seeded onto scaffolds. Aggrecan expression by cells was decreased on PCL and PLLA scaffolds but increased on PCL:PLLA. These results suggest that, all of the scaffolds, especially PCL:PLLA, favored chondrogenic differentiation of HTGSCs.