Establishing And Studying Of Injectable Hydrogel Combined With Native Growth Plate Extracellular Matirx Applied To Tissue Engineered Epiphyseal Cartilage

Growth plate injury in children is prone to lead to bone bridge formation and varus orvalgus deformity,which is one of the common clinical disease.Nowdays, excisingbony bridge and inserting fat as interposition material have been used todeal with the growth plate injury whose damage area are less than35%clinically.However the efficacy is poor for those damage area are more than50%,because the implant has no growth capability. In recent years,tissue-engineeredepiphyseal cartilages bring new hope in the treatment of growth plate injury.While so far, tissue engineering materials such as collagen gel, gelatin sponge,agarose, chitosan, demineralized bone matrix can not provide adequate extracellularmatrix microenvironment. Injectable tissue engineering systems are defined by theirability to be implanted without invasive surgery. However, the extracellular cartilagematrix components in common injectable gels are inadequate, the epiphyseal cartilagecan not fully meet the specific physiological requirements.In our study, weestablish injectable hydrogel applied to tissue engineered epiphyseal cartilage with anew biomaterial which containing allogenic articular cartilage extracellular matrix（CACECM）and calcium alginate, and transplant growth plate chondrocytes intoinjectable hydrogel co-cultured in vitro.Objective: Segragate and extract native extracellular matrix in fetalcattle, produce injectable hydrogel applied to tissue engineered epiphyseal cartilagewith a new biomaterial which containing allogenic articular cartilage extracellularmatrix（CACECM）and calcium alginate, and examine the physic-chemistrycharacter and biocompatibility.Methods:(1) Growth plate cartilages in the distal of femur and proximal of tiblainin fetal cattle were shattered into microfilament by the means of pulverization technology.CACECM was obtained by the methods of differentcentrifuge and organic solvent.Doing quantitative detection of DNA and GAG on theinjectable hydrogel including of ALG and CACECM.(2)Growth platechondrocytes were collected from New Zealand rabbits at2weeks old, amplified invitro, and inoculated into CACECM to observe their pathological change andhistocompatibility. The compound was injected to the backsidesubcutaneously．Specimens were harvested8weeks later and analyzed by histologyand physics.Results:(1) The CACECM included extracellular matrix component, such ascollegan Ⅱ and GAG. The injectable hydrogel has good biological function.(2)Growth plate chondrocytes grew and proliferated actively in the injectable hydrogel,and they also secreted extracellular matrix, which showed that theinjectable hydrogel derived extracelluar matrix had sutible biocompatibility.Moreover the injectable hydrogel had suitable degradation.Conclusion:It is a promising way of combinig calcium alginate and CACECM asbiomaterial for injectable hydrogel applied to tissue engineered epiphyseal cartilage.