Experimental Study On Regenerating Of Articular Cartilage Defects In Old Rabbits With Allogeneic Bone Mesenchymal Stem Cells Derived From Young

Objective: Compare the different abilities of proliferation and growth kinetics on Bone Mesenchymal Stem Cells (BMSCs) which is from young and old rabbits respectively in vitro. Meanwhile, make combination of BMSCs from young rabbits and scaffolds to form the tissue engineering cartilage. Allogeneic-transplant these composites into the cartilage defects, observe the feasibility of BMSCs allograft, and compare the outcome between the young allograft and the old snygraft.Method: Mesenchymal stem cells were isolated and purified from young rabbits and old rabbits by whole bone marrow culture combined with differential attachment technique. After the BMSCs were propagated to the 5th generation, draw their curves of growth and kinetics actives by the method of counting cells and MTT respectively. When the cell's number is enough, BMSCs was seeded into the collagen I scaffolds, after 72-hour co-culturing, the cell-adhered collagen I was implanted into the articular cartilage defects at the intercondylar fossa of the distal femur in the old rabbits, the other side is snygraft BMSCs-college I. the rabbits were sacrificed 6th weeks and 12th weeks after the operations and the specimens were examined histologically for morphologic features, and stained immunohistochemically for type II collage. Specimens of reparative tissue were analyzed with use of a semi quantitative histological grading system and by mechanical testing called Wakitani test at 12th weeks after the operation.Result: There was on obvious age-related variation in cell shape and size, they all displayed a fibroblat-like morphlogy, polygon and ellipsal, But there were differences on the growth abilities and kinetics actives between young rabbits and old ones (p<0.05) in vitro. In the growth and MTT curves, the time to reach the platform for BMSCs from young ones was earlier than the old ones (p<0.05), and its saturation density on the platform was also higher than the old ones. The outcomes of young BMSCs allograft into the articular cartilage defects were very good. They were as similar as the normal cartilage round, and immunity exclusive reactive won't found either. With use of a semi quantitative histological grading system, we find young BMSCs- scaffolds-transplanted group were significant better than the scaffolds only group (p<0.05), but there were no significant differences between young BMSCs-scaffolds-transplanted group and old BMSCs- scaffolds-transplanted group (p>0.05).Conclusion: Comparing the BMSCs from old rabbits, the BMSCs from young rabbits is isolated and purified more easily, which have highly success rate. Further, its growth abilities and kinetics actives is also better than the latter. The outcomes of young BMSCs allograft into the articular cartilage defects are good, but there were no significant differences between young BMSCs- scaffolds-transplanted group and old BMSCs- scaffolds-transplanted snygraftly. In a word, young BMSCs is a excellent seed cells in the tissue engineering field.