ABSTRACT
To investigate the formation of tissue engineered cartilage using polyglycolic acid (PGA) as three dimensional scaffold seeded with allogenic chondrocytes. First, chondrocytes were harvested from rib cartilage of one week old infant rabbits by collagenase digestion.The isolated cells were cultured in vitro for 2～3 generations, and then the cell suspension was concentrated. Next, the suspension was seeded onto PGA scaffolds soaked with poly l lysine. Then, scaffold chondrocyte constructs were transplanted into subcutaneous tissue of adult rabbits. Finally, the chondrogenesis was studied histologically at various periods. The results showed that chondrocytes were well distributed on the PGA scaffolds in the period of culture in vitro, and could secrete matrix around one week after seeding. 4 weeks after transplantation, the immature cartilage was regenerated in recipient animals. But some inflammatory cells surrounding the new cartilage and some PGA fibers were observed. 8 weeks after transplantation, mature cartilage with abundant matrix was obtained. PGA fibers were not found. This study proves that it is possible to regenerate new cartilage in animals possessing immune function by seeding allogenic chondrocytes onto PGA scaffold. Rejectionreaction is not strong.
ABSTRACT
Objective To investigate the inhibitory effects of exogenous WAF 1 S gene on human laryngeal cancer Hep 2 cell line, and to explore the potential use of WAF 1 S in gene therapy for laryngeal cancer. Methods A eukaryotic expression vector containing 2 1kb human full length WAF 1 S cDNA was transfected into human laryngeal cancer Hep 2 cell line by using lipofectamine. Expression of exogenous WAF 1 S gene was detected by dot blot hybridization. By using Western blot and confocal microscope, expression of p21 protein was quantitatively analyzed in situ . The growth state of transfected Hep 2 cell was determined by flow cytometry and MTT. Results It was found by dot blot hybridization that WAF 1 S gene could express in Hep 2 cell. The expression of the exogenous p21 gene in Hep 2 cells was markedly higher than that in the control group. It was confirmed with flow cytometry that WAF 1 S gene could induce apoptosis of laryngeal cancer Hep 2 cell line, and the progression of cell cycle was arrested at G 1 phase. Conclusion Laryngeal cancer cells could be arrested at G 1 /S phase and the growth of the cells could be significantly suppressed by exogenous WAF 1 S gene