| Objective: Cartilage is a highly differentiated tissue and therefore has a limited capacity for self-repair.The treatment of articular cartilage defects has been a problem in orthopedic surgery up to now. The defects may be caused by trauma or evolved during the course of diseases.The large defects at articular cartilage are often repaired by fibrocartilage rather than normal hyaline cartilage.The repairing fibrocartilage tissues are different from hyaline cartilage in either biochemically or biomechanically and It ultimately deteriorates. In spite of extensive research on stimulating repair of articular cartilage defects No reliable methods to achieve this goal which has been described so far.Recently,there are many investigations to accelerate repairing of the defects of articular cartilage and improve the quality of repairing tissue. The transplantation of engineered chondrocytes may be an ideal method. Nowday, The study has received more attention how to select the biodegradabile scaffolds which can provide 3-dimensional tissuelike enviroment for cell proliferation. Howevre,the study has been paid little attention to which the repair of full-thicness articular cartilage defect with a composite of engineered chondrocytes andPluronicF-127. One object of this study is to seek for the feasibility to repair the full-thickness articular cartilage defect with the method of PluronicF-127 carried engineered chondrocytes homotransplantation.Material and Method: A total of 27healthy adult rabbits were randomly divided into three groups:A PluronicF - 127 filled group, B void control group , C test group . Pluronic F-127 was used as a vehicle of chondrocytes which were obtained from 4 months old new Zealand rabbit and cultured in vitro. The mixture of PluronicF-127 and cultured chondrocytes was transplanted into the defects of articular cartilage that had been made previously with 03.5mm drill (group C) . At 4,8,12 weeks after the operation, we harvested the repair tissue, and evaluated the tissue with the macroscopic histological electronmicroscopic The quality of repair tissue was evaluated blindly with use of a histological grading scale made by Wakitani et a!0 Results: The chondrocytes in the composite of Pluronic can proliferate well. The new tissues which filled the entire area of the defects at forth weeks postoperation were distinguished. At eight and tweleve weeks after transplantation, the gross appearance of the defects was similar to that of normal cartilage around the defectso In void contra! group and Pluronic-filled group, After 4 weeks of the operation, there is a dent on the surface of repair tissue .After 8 and 12 weeks, The repair tissue was lack of plastic and had an irregular surface,, At the same time The repairing process in chondrocytes-Pluronic group was faster and better than the both control groupso At 4 weeks, the new tissue filled the entire area of the defects, At 8 and 12 weeks, the gross apperance of the defects was similar to that of normal cartilage around the defects. The cartilage was slavedin some superficial area. Pluronic had been absorbed completely at 8 to 12 weeks. The mature hyaline chondrocytes and type II collagen were found with screening electron microscopy(SEM). There was no statistical difference between control group and pluronic group, (p>0.01).according to histological grade scale, but there was a significant statistical difference (p<.0o 01) between test group and other twe groups,,Conclusion: The mixture of PluronicF-12 and cultured chondrocytes can repair successfully the cartilage defect of femoral condyle of rabbit knees in the mode of hyaline cartilage. PluronicF-127 can be seemed as a safer and effective vehicle of engineered chondrocytes. It is highly promising for the treatment of articular cartilage defects. The study may provide a new nontraumatic method for the extensive and irregular articular cartilage defects.Postgraduate: Zhai Xi cheng (Orthopedics) Directed by: Prof. Wang Yingzhen... |
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