| Objective: The purpose of this study was to compare thecurative effect of repairing segmental bony defects remained theperiosteum treated with autologous bone marrow stromalcells(BMSC) or red bone marrow(RBM), which provide thereasonable method for clinical practice.Methods: 48 adult New Zealand white rabbits weredivided into four groups(A, B, C and D) randomly, 12 in eachgroup. 15 ㎜segmental defects were created in the two radiusof the animal, the periosteum was remained. The rabbits ofgroup A were treated by type I collagen matrix combined withBMSC, and the group B treated by type I collagen matrixcombined with RBM. Wet type I collagen matrix was implantedinto the group C, while the group D was implanted into nothing.Rabbits were sacrificed at 2, 4 and 8 weeks respectively aftersurgery, the specimens were observed in general, taken theposteroanterior radiographs of ulna and radius, and graded thescores by Lane-Sandhu standard. Otherwise, the specimens werestained with HE for histological examination and gettinghistological scoring by Nilsson standard. The specimens of the 8weeks were divided into two parts, one part was observed withabove-mentioned ways, the other was conserved in super lowtemperature refrigerator(below﹣80℃), and taken three pointbending test with INSTRON5544 experimental machine. All ofthe data was assessed with the SPSS 11.5 statistics software.Results: general observation results: Callus increased andreconstructed gradually in specimens of group A, and filled inthe bony defects area in 2 weeks, it did not finishedreconstruction until 8 weeks postoperation. However thespecimens of group B didn't fill in the bony defects area until 8weeks, and the samples in group C and D formed a little callus,covering less than half of the bony defects area.The results of X-ray: The shadow of callus in every groupspread gradually, especially in Group A and B. The shadow ofgroup A had filled in the bony defects area after 2 weeks ofimplantation, till 8 weeks the callus increased and reconstructedclearly, meanwhile bone marrow cavity had recanalized.Contrast to group A, the shadow of group B was fewer, didn'tfill in the bony defects area until 8 weeks. The shadow of groupC and D covered less than half of the bony defects area until 8weeks, only at the side of the periosteum, while the amount ofcallus is fewer than the group A and B clearly. By analysis ofvariance, there is significant difference among all the groups indifferent periods(p﹤0.05), there is no significant differencebetween group C and D only (p﹥0.05).The histological results: 2 weeks after operation, thespecimens of group A could be found many new-formed osteoid,original trabeculae, active osteoblasts, and no inflammatorycells invaded. Much neonatal blood vessel was observed in theactive periosteum, around which chondralcytes andendochondral ossification could be found, but intramembranousossification was presented more active. The specimens of groupB could be found many chondralcytes and more originaltrabeculae scattering in the collagen matrix and around theremained periosteum, endochondral ossification was presentedmore active. But the samples of group C and D were primarilyfilled with connective tissue, a large amount of inflammatorycells, original chondralcytes could be found around theremained periosteum and no bone forming phenomenon wasfound. 4 weeks after the implantation, the specimens of group Acould be found newly formed bone tissue which was moremature. Obviously, there were trabeculae forming, looking likewoven bone, which had connected the two bone breaks, andthere was no bone marrow cavity in the space. The samples ofgroup B could be found the scattered osteoid and new-formedtrabeculae, accompaning with chondralcytes or fibrocytes, noapparent woven bone formed. The samples of group C and Dwere still filled with connective tissue primarily, manychondralcytes and endochondral ossification could be seenaround the remained periosteum, around which a little originaltrabeculae could be found. At 8 weeks later, mature trabeculaecould be found changing into new lamellar bone in thespecimens of group A, the callus,reconstructing could be foundapparently and bone marrow cavity had recanalized. In samplesof group B, woven bone had been formed, and bone marrowcavity had not recanalized. In the group C and D, connectivetissue was the most in the bony defects, a few chondralcytes andimmature trabeculae could be found only around the remainedperiosteum, and the two bone breaks had already blocked.Histological score analysis results: There is significantdifference among all the groups in different periods(p﹤0.05),but there is no significant difference between group C and Donly(p﹥0.05).Results of biomechanical testing: In 8 weeks, the bendingloading at breakpoints for the specimens of group A, B, C and Dwere (216.15±38.84)N, (163.15±23.45)N, (99.42±16.38)N,and (85.30±13.20)N. The statistical analysis shows that there issignificant difference among the four groups(p﹤0.05). Thefurther comparison showed there is no significant differencebetween group C and D only(p﹥0.05).Conclusion: 1. Bony defect remained the periosteum is asuccessful way to imitate the clinical condition, it may be abetter model for fresh traumatic bony defects. 2.CultivatedBMSC in vitro have a powerful ability to form bone tissue. Itscurative effect of repairing segmental bony defects remained the...
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