| ObjectiveArticular cartilage seldom has ability to repair after being injured. There was not effective treatment in clinic today .The question how to repair injury of articular cartilage has become a hot topic of articular surgery because of the importation of articular cartilage in joint function. Recent decade, the rapid development of the tissue engineering brought out essential change in repairing articular cartilage injury. The basic principle is: separate seed cells and then they were integrated with cell vesicle, marking cells-vesicle compound body. Compound body was transplanted into defect of articular cartilage. Cells proliferate and make new cartilage tissue so as to reach aim of repairing injured articular cartilage. Chondrocytes and mesenchymal stem cells (MSCs) derived from bone and cartilage membrane were not suitable to act as seed cells because of high cost, limited origin, two operations and low proliferate abilities. On the contrary, bone MSCs were suitable to act as seed cells of the tissue engineering of articular cartilage in virtue of adequate origin and ease gain.Materials and Methods15 Chinese rabbits, 2.0~2.5kg, without limits in age and sex. Bone marrow was aspirated under sterile condition from the iliac crests and tibia condyles of rabbits. A 5-6ml sample was centrifuged to separate bone MSCs cells and culture in vitro. The MSCs of passage 2~3 were collected. Cells with density of 2xl06/ml were seeded into type I collagen gel and then the mixture was allowed to gel in incubator for ten minutes. This gel that contained bone-marrow mesenchymal stem cells was transplanted into the cartilage defects within two hours. The right knees were experimental groups and the left ones were control groups. A cutting cylinder whose external diameter was 4mm in patella trochlea of femur created the defects. The experimental group defects were filled with bone MSCs from the same rabbit. The control group was transplanted with cell - free collagen gel. All animals were allowed to move freely after surgery. 5 rabbits were killed in 4, 8, 12 weeks respectively. The samples were assessed in gross and histology. Each sample was graded with use of a histological scale quoted from Wakitani. The scale was cell morphology, matrix-staining, surface regularity, thickness of cartilage and integration of donor with host.Results1. Bone MSCs gain easily. MSCs of passage 1-3 proliferated rapidly and grew stably in vitro and may be well used in autogeneous cartilage tissue engineering.2. Macroscopic evaluation: At 4 weeks, the defects of experimental group were filled with hyaline-like white smooth reparative tissue. The margins of the defects were unclear; At 8 weeks, it was generally difficult to discern theboundary between the host and the reparative tissue. At 12 weeks, the degree of transparention decreased continuously. In the control group, the defects were left empty at 12 weeks, although filled with fibroblastic tissue.3. Microscopic evaluation: the defects of experimental group were replaced by the formatting neo-cartilage that showed positive staining of toluidine blue at four weeks. The neo-cartilage was modeled to normal cartilage at eight weeks and was similar to the surrounding cartilage at twelve weeks. But in the control group, the defects were not repaired by cartilage tissue at every stage and were filled with fibroblastic tissue, which were negative staining of toluidine blue. Statistical showed that the score was the lowest at four weeks, the score of experimental group was better than the control group at every stage.Conclusions1. The plentiful and safe bone MSCs is an expected seed cell of cartilage tissue engineering.2. The effect of repairing defects in articular cartilage by transplanting bone MSCs is distinctly better than that of the control group.3. The three elements help bone transplanted MSCs differentiate into cartilage tissue: one, physiological environment of lack of blood and oxygen; two, continuous kinetic friction; three, collective e...
|
PDF Full Text Request