Experimental Studies On Repairing Articular Cartilage Defect Of Rabbits With PLGA/type-Ⅱ Collagen/rhBMP-2/bFGF

Object: To evaluate the effectiveness and feasibility of PLGA coated by type-Ⅱcollagen with rhBMP-2 and bFGF to repair rabbit articular cartilage defect. Toexplore the cooperative action mechanism between rhBMP-2 and bFGF in repairingrabbit articular cartilage defect.Methods: 45 adult New Zealand rabbits were randomly divided into five groups.There were 15 rabbits in each group. Full-thickness defects were made on the femoralmedial condyle of right knee in 45 rabbits. Group A were treated with PLGA/type-Ⅱcollagen/rhBMP-2/bFGF composites, Group B were treated with PLGA/ type-Ⅱcollagen/rhBMP-2 composites, Group C were treated with PLGA/type-Ⅱcollagen/bFGF composites, Group D were treated with PLGA/type-Ⅱcollagen only,and Group E were untreated. Group A, group B and group C were called experimentalgroup, group D and group E were called control group. The rabbits were sacrificedand specimens were procured from the femoral medial condyle in 4,8,12 weekspost-operation, each time three rabbits were sacrificed in each group. Each case wasexamined histologicaly and graded with O'Driscoll. Immunohistochemical methodwas used to detect the type-Ⅱcollagen in 12 weeks case and coloring of specimenswere quantificated by Leica QWIN image analysis system. In 12 weeks groupcartilage cells were detect by transmission electron microscope.Results: The finding of general and histological study showed that experimentalgroup have visible promotional action in repairing articular cartilage defect. Thegrades of O'Driscoll were higher in group A,B and C than in group D and E withsignificant difference(P＜0.05); The grades of O'Driscoll were higher in group A thanin group B and C with significant difference(P＜0.05); there are no significantdifference between group D and group E. Immunostaining with an antibody against type-Ⅱcollagen in 12 weeks group showed the group A,B,C were highest than thegroup D,E and the group A were highest than the group B,C with significantdifference (P＜0.05).Conclusion: Three composites with growth factor have visible promotional actionin repairing rabbit articular cartilage defect, and the group A have a more idealeffect. The PLGA/type-Ⅱcollagen composites can act as carrier material ofrhBMP-2 and bFGF. There were cooperative action between rhBMP-2 and bFGFunder just the right amount of quantity (0.5mg:50ng) in repairing rabbit articularcartilage defect.