| Human umbilical cord blood-derived mesenchymal stem cells (humanumbilical cord blood mesenchymal stem cells, HUCBMSCs) in the role ofosteogenic agents directed differentiation into cells with the characteristicsof bone cells, which then transplanted the induced and the non-inducedHUCBMSCs into the rabbit fracture model, the transplanted cells wasobserved on fracture healing in order to find out a suitable transplant cellsfor clinical applications in theoretical evidence.Under sterile conditions, isolated and cultured HUCBMSCs by densitygradient centrifugation and adherent culture, took the3rd generationHUCBMSCs application osteogenic agent to induce ossification forosteogenic two weeks.4~5months72healthy New Zealand white rabbits,weighing2.0~2.5kg, male or female, with a wire saw transverse fracture ofthe right tibia produced, were randomly injected into the fracture siteHUCBMSCs group (induced group)24only, HUCBMSCs group(non-induced group)24and the saline group (control group)24, three daysafter the establishment of3Groups in the fracture model, with theassistance of C-arm, on the perpendicular to the fracture site of the needle,were injected at a concentration of1×107cells/ml suspension osteogenicafter HUCBMSCs1ml,1×107cells/ml HUCBMSCs1ml suspension thesame quantity of saline water. After2,4,6and8weeks six rabbits ofeach group were randomly selected cell transplant, then were shot righthind tibia X-ray, then were killed by using air embolism.Took the wholetibia, measured the bone densityand did biomechanical testing, finally, took the fracture line distance of each5mm organizations, fixed, decalcifiedparaffin embedded, serial sections were stained part of routine hematoxylin-eosin staining, observed under ordinary microscope. The other part wasdetected by HUCBMSCs.The experimental data immunofluorescencestaining of BrdU-labeled statistics were analysed by using SPSS17.0.X-ray examination and fracture healing results of X-ray score analysisshowed that induced group, non-induced group of fracture healing wassignificantly faster than the control group, while induced group healedfaster than non-induced group. Bone density test results showed, at the2,4and6weeks after cell transplantation, induced group and non-inducedgroup’s bone mineral density were higher than the control group, thedifference was statistically significant (P<0.05), while in the first eightweeks induced group and non-induced group’s bone mineral density werelower than the control group, the difference was statistically significant(P<0.05); at2and4weeks, the induced group’s bone mineral density werehigher than non-induced group’s, the difference was statistically significant(P<0.05), while at the first6,8weeks, the induced group’s bone mineraldensity were lower than non-induced group, the difference was statisticallysignificant (P<0.05). Biomechanical results showed that at4and6weeksafter cell transplantation, induced group were higher than non-inducedgroup and control group in the maximum failure load, the difference wasstatistically significant (P<0.05), but lower than non-induced group andcontrol group at the8weeks, the difference was statistically significant(P<0.05); at4,6and8weeks non-induced group were higher than controlgroup in the maximum failure load, the difference was statisticallysignificant (P<0.05); at4and6weeks after the cell transplantation theinduced group and non-induced group were higher than the control groupin the maximum displacement, the difference was statistically significant(P<0.05), while the induced group were higher than non-induced group inthe maximum displacement, the difference was statistically significant (P<0.05); Histological observation and scoring results analysis showed thatinduced and non-induced group fracture healing process is faster than thecontrol group,and the healing quality is better than the control group, whilethe induced group fracture healing process is faster than non-induced group,and the healing quality is better than non-induced group.Immunofluorescence test results indicated that the induction of celltransplantation group and non-induced group organization fracturefragments are visible under a fluorescence microscope at each timepoint.The fragments scattered in the green fluorescence positive cells,while in control group there were no positive cells.We found that the induced HUCBMSCs after osteogenic and theHUCBMSCs in fracture healing have played a catalytic role. However, theefficacy of osteogenic HUCBMSCs is more significant; The mechanism ofHUCBMSCs after transplant to promote fracture healing may be related tothe directly involved in fracture healing under the influence of themicroenvironment. |
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