Development Of A Osteochondral Composite Utilizing LDBM,alginate And Chondrocytes For Treatment Of Cartilage Defect

ObjectiveMimic the anntomy of natual osteochondral to develop an integrative scaffold of layered demineralized bone matrix. Observe the feasibility of the "chondrocyte-LDBM scaffold " osteochondral composite utilizing Alginate as a carrier of cells implanted in rabbit articular cartilage defect. Methods1. Preparation and characterization of 3-D porous scaffolds of LDBMbovine cancellous bone of femoral metaphyseal(diameter 4mm, height 10mm)was used as scaffold materials, through degreased, acellular after a series of chemical treatment. The lower half of the column was buried in bone wax for layered decalcifying to develop an integrative scaffold of LDBM for osteochondral tissue engineering. The scaffolds were evaluated grossly,histologically,SEM and observe its degradation rate and mechanical properties.Cells were cultured with LDBM and CCK-8 curve was used to analyze effect of cells on LDBM and also observed by SEM.2. "chondrocyte-LDBM scaffold " osteochondral composite repair articular cartilage defectsThe LDBM scaffold was immerse in the suspension of Alginate and chondrocytes. Calcium chloride solution was loaded to the scaffold subsequently to develop the "chondrocyte-LDBM scaffold " osteochondral composite. Twenty-four New Zealand rabbits were divided into three groups randomly after manufactured bilateral knee cartilage defects: control group, LDBM group and composites group.The rabbits were killed at 3 and 6 months after operation in each group,and the repairative tissue samples were evaluated grossly,histological and immunohistochemically and evaluated the effect of repairative tissue samples by Wakitani pathology score system.3. statistical analysisUse SPSS 17.0 statistical software for data processing. Data as mean±standard deviation, ANOVA was used to evaluate the differences between groups with an LSD comparisons procedure, P < 0.05 illustrates differences statistically significant. Results1. LDBM scaffold was loose and porous structure. and the part of demineralized and the undecalcified is natural transition with a clear boundary. SEM observation LDBM retain the original bone lumen system, uniform pore size distribution, material gaps between the internal traffic condition, junction connections are intact, and no breakage. MTT assay result is a stent non-cytotoxic, Chondrocytes cultured in vitro, SEM and CCK-8 shows the good results of adhesion and proliferated.2. The full-thickness articular cartilage defect 6 months the composites group has show a better repair effect with a smooth surface and hyaline-like tissue repair, the repaired tissue was integrated with the surrounding tissue. The LDBM group has a certain degree of cartilage-like tissue repaired, relatively smooth surface.The control group has only a small amount of fibrous tissue repair, sag significantly. Gross and Wakitani score results showed that the composite group scores were better than LDBM and control groups at each time point and have a significant difference than LDBM group and control group. ConclusionThrough degreased, acellular after a series of chemical treatment,The bovine cancellous bone is was buried in bone wax for layered decalcifying to develop an integrative scaffold for osteochondral tissue engineering. The two phase allogeneic LDBM scaffold has good biocompatibility and mechanical properties. Calcium chloride solution was loaded to the scaffold subsequently to develop the "chondrocyte-LDBM scaffold " osteochondral composite, which has show a better repair effect in rabbit knee joints.it also provides a new option for osteochondral tissue engineering composite for cartilage defects.