| Objective:To investigate the repair effect and mechanismof femoral head necrosis treated by transplantation of bonemarrow stromal cells and to provide reasonable theory andtherapy to clinic.Methods:1 cell culture .Bone marrow were obtained fromrabbits posterior iliac crest and inoculated in 6-welldishes.Every well contained 5 milliliter DMEM supplementedwith 20 percent of fetal bovine serum and 10-8 molardexamethasone.These 6-well dishes were placed into ahumidified incubator at 37 degrees Celsius. The medium werechanged on the fifth day.When the cells were confluent on thebottom of well,these cells must be subcultured.The thirdgeneration of cultured cells were inoculated in gelatinsponge.Every piece of gelatin sponge to be prepared fortransplantation contained 100,000 cells.A part of the thirdgeneration of cultured cells were induced bydexamethasone,ascorbate and ?-glycerol phosphate. The thirdgeneration of cultured cells with inducement or withoutinducement were identified by alkaline phosphatasestaining,bone morphgenetic protein immunocytochemistrystaining and mineralized node staining at 1,2,3 weeksrespectively.2 Animal treatment. Femoral head necrosis was induced byfreezing method with liquid nitrogen in 46 rabbits.All of theinduced rabbits were divided randomly into four groups .GroupA as animal model group contained 10 rabbits.There were 12rabbits in group B,C,D respectively,group B as coredecompression group, group C as autograft group, group D asallograft group.In group A,a rabbit was sacrificed at 3,7 daysrespectively after freezing, two rabbits were sacrificed at 2,4,6,8weeks respectively after freezing.Three rabbits in group B,C,Dwere sacrificed at 2,4,6,8 weeks respectively after operation.Allof the femoral head obtained were examined byradiograph,microscope and tissue image analysis.Results:1When the medium were changed on the fifthday,some fibroblast-like unites were found growthing on thebottom of the well.The cells anchored in 2-4 hours afterdigesting,and were confluent on bottom of the well.The logphase was from 2 days to 7 days.The population doubling timewas at 48 hours.Bone marrow stromal cells with or withoutinducement were positive by alkaline phosphatase staining andwere negative by bone morphgenetic proteinimmunocytochemistry staining and mineralized node staining at1,2,3 weeks. Bone marrow stromal cells with inducement werepositive by alkaline phosphatase staining at 1,2,3 weeks andwere positive by bone morphgenetic proteinimmunocytochemistry staining and mineralized nodes stainingat3 weeks.2 In Group A,three days later afterfreezing ,osteocyte,chondrocyte and bone marrow werenecrotic,and trabeculae kept intact.The minimum of the emptylacunae rate was 73%.The maximum of the empty lacunae ratewas 95%. After two weeks,repair process began.Cartilage repaircame from two sources.One source which chondrocytepresented spindle shape was from synovial membrance andfemoral head ligment .The other sourse was located in the zoneof proliferation of cartilage, which chondrocyte presentedroundness or oval shape.Bone repair had two kinds of typeswhich were intramembranous ossification and endochondralossification.Two weeks later after freezing ,new-formed boneeither appeared in the intertrabecular space or covered the deadtrabeculae.At 8 weeks, new-formed bone increased,in themeantimes,a part of dead trabeculae became thin,irregular orbroken.In group B, two weeks later after operation, Someinflammatory cells appeared in the center of the drilledhole.Only a few amount of osteoblasts were in the drilledhole.With the time going,at 8 weeks, the drilled hole were full ofmarrow.In group C, Two weeks later after operation, there werealso some new-formed bone appearing around the drilledhole,but there were a large amount of osteoblasts appearing inthe drilled hole.At 4 weeks, the drilled hole were full ofnew-formed trabeculae.At 8 weeks, the trabeculae were mature... |
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