The aim of this study was to evaluate the potential for restoration of a large cartilage defect in the goat knee with hydroxyapatite (HA) loaded with chondrocytes. Isolated chondrocytes were suspended in fibrin glue, seeded on top of the HA, and then the composite graft was implanted in the defect. After transplantation, cell behaviour, newly synthesised matrix and the HA–glue interface were assessed histologically after 2, 4, 12, 26 and 52 weeks. Special attention was paid to the incorporation process of HA in the subchondral bone and interactions between this biomaterial and the fibrin-glue–chondrocyte suspension.
Chondrocytes in the glue proved to survive the transplantation procedure and produced new metachromatically stained matrix two weeks after implantation. The glue–cell suspension had penetrated the superficial porous structure of the HA. Four weeks after surgery, islands of hyaline-like cartilage were observed at the HA–glue interface. A layer of fibrous tissue was formed surrounding the HA graft, resulting in a relatively instable fixation of the HA in the defect. This instability of the graft in the defect, possibly together with early weight bearing, resulted in a gradual loss of the newly formed hyaline cartilage-like repair tissue. Progressive resorption of the HA occurred without any sign of active bone remodelling from the host site. One year after surgery part of the defect which extended down to the cancellous bone had been predominantly restored with newly formed lamellar bone. Only small HA remnants were still present at the bottom of the original defect. Resurfacing of the joint had occurred with fibrocartilaginous repair tissue.
The absence of adequate fixation capacity of the HA near the joint space resulted in a relative instability of the graft with progressive resorption. Therefore, HA is not a suitable biomaterial to facilitate the repair of large articular cartilage defects. 相似文献
Objective To investigate the effectiveness and mechanism of transplantation of autol-ogous bone marrow in treating femoral head necrosis. Methods Sixty New Zealand rabbits were randomly divided into groups A,B,and C after establishment of the models of femoral head necrosis. The left femoral head served as the control one,and the right as the experimental group. The mitoxantrone (0.1 mg/kg) with the help of DSA was injected into the femoral head of group A. One ml autologous bone marrow was injected into the femoral head of group B. In group C,mitoxantrone (0. 1 mg/kg) was injected,and 72 h later,1 ml autologous bone marrow was injected. Four months later,all rabbits were killed,and the femoral heads were removed and observed histologically and electron microscopically. Results The number of necrotic osteoclasts in groups A and B showed no significant difference ( P > 0.05 ), ande in group C, the number of necrotic femoral heads at the left and fight sides was 40. 60±4.11 and 21.33±2.16 respec-tively ( P < 0.05 ). At the experimental side of group C, the structure of majority bone cells was clear and intact,and necrosis was occasionally seen. Conclusion At the cellular level, local chemotherapy and au-tologous hematopoietic stem cell transplantation had certain effectiveness for aseptic necrosis of the femoral head. 相似文献
Two children with Alport's syndrome are described, who developed anti-glomerular basement membrane (GBM) antibody-mediated nephritis after renal transplantation. The reactivity of antibodies in their serum with collagenase-solubilized normal GBM was examined by SDS-PAGE with one- and two-dimensional immunoblotting. The specificity was compared with that of antibodies present in serum from a patient with Goodpasture's syndrome, and a mouse monoclonal antibody (MCA-P1), directed against the Goodpasture antigen. All reacted in a similar way with collagenase-solubilized GBM. Since abnormalities in the composition of the GBM are present in Alport's syndrome, it is proposed that differing antigen composition of GBM in the host compared with the donor kidney, together with transplant rejection, may have provoked the development of post-transplant anti-GBM antibodies. 相似文献