| Objective: For a long time, cartilage defect has been faced by the clinical problem. Traditional treatment methods, such as grinding, micro-fractures, cartilage and perichondrium transplantation, have poor effects. In recent years, the vigorous development of tissue engineering has brought a new way for cartilage repair. Choose the ideal seed cells for cartilage tissue engineering is essential. Bone-marrow-derived mesenchymal stem cells (MSCs) is considered the most promising seed cells for tissue engineering. However, there are still many problems with culture and induction of MSCs. For example, complicated operation, easily contaminated, and the cells are easy to variation after leaved the three-dimensional structure of the body. It is not very clear to differentiation mechanism of MSCs. How to control the proliferation, how to control the directional differentiation of MSCs at the appropriate time remain to be further studied. Bone-marrow-derived mononuclear cells(BM-MNCs), including hematopoietic stem cells, MSCs, endothelial progenitor cells and stromal cells, are the mixed cell populations. Studies have shown that, compared with a purified cell of bone marrow, BM-MNCs can provide the micro-environment for cells growth and differentiation. It is good that BM-MNCs are transplanted directly after the separation. Therefore, using uncultured BM-MNCs as seed cells to repair of cartilage defects can prevent many problems on MSCs culture and induction. In this study,we examined the feasibility of autologous uncultured BM-MNCs transplantation in a full-thickness articular cartilage defect model and attempted to find a safe and effective method to repair articular cartilage defects clinically.Methods: The 36 rabbits were randomly divided into three groups, 12 rabbits in each group. Experimental group was taken 5ml marrow from the left femur, then autologous BM-MNCs were separation and extraction. After establishing models of right knees articular cartilage defect, the experimental group implanted autologous uncultured BM-MNCs - autologous fibrin gel complex; experimental control group implanted autologous fibrin gel; blank control group implanted nothing. Six rabbits were killed at 8 and 12 weeks after transplantation in each group, and the reparative tissue samples evaluated grossly, histologically and immunohistochemically were graded according to the gross and histological scale.Results:1 Gross observation: Eight weeks after transplantation, the defects were filled with milky white tissues in the experimental group. The boundary of regenerated tissues was blurred. In experimental control group, the colour of reparative tissues was light yellow and the boundary of reparative tissues was clear. In blank control group, the defects were partially filled with fibrous tissues, there were still large holes. Twelve weeks after transplantation,the reparative tissue surface was smooth, similar color with the surrounding cartilage, the boundary was blurred in the experimental group. In experimental control group, reparative tissue surface was rough and obviously depressed. In blank control group, the defects were partially filled with milky white tissues, there were still obvious holes.2 Histological observation: Eight weeks after transplantation in the experimental group, the surface of reparative tissue was smooth. Chondrocytes gradually become round, oval and bigger. There were some cartilage capsules and cartilage lacunas. However, compared with normal cartilage, reparative tissue have more chondrocytes, and the morphology and arrange in order of chondrocytes were little abnormal. Reparative tissue thickness is greater than the thickness of normal cartilage.In two control group , defects were filled with a little fibrous tissues. Twelve weeks after transplantation, defects were repaired by hyaline-like cartilage in experimental group. The morphology and arrange in order of chondrocytes were similar to normal, and extracellular matrix toluidine blue staining was tend to normal. The reconstruction of cartilage and subchondral bone was good.The defects of the two control group were still partially repaired by fibrous tissues.The statistical analysis on the histological gradings at 8 weeks and 12 weeks showed that experimental group was significantly better than experimental control group and blank control group (P <0.05), blank control group was better than experimental control group (P <0.05), each group at 12 weeks was better than itself at 6 weeks (P <0.05).3 Immunohistochemistry staining of type-â…¡collagen: Twelve weeks after transplantation, the cytoplasm and extracellular matrix was strongly positive in type-II collagen staining, with many yellow-brown drops in experimental group. However there were only some positive cells in twe control group.Conclusion:1 Transplantation of the uncultured autologous BM-MNCs combined autologous fiber gel on the full thickness defects of the articular cartilage is a promising approach to the treatment of cartilage defects.2 Transplantation of the autologous fiber gel without seed cells on the full thickness defects of the articular cartilage is not conducive to the repair of articular cartilage defects...
|
PDF Full Text Request