Objective To investigate whether the administration of tissue engineering technique can prevent the degeneration process after allograft total disc transplantation. Methods Canine nucleus pulposus cells were isolated routinely. The second passage of nucleus pulposus cells labelled by PKH-26 were injected into the cryopreserved allograft discs to construct a "tissue-engineered" allograft discs ( Group A ). Untreated allograft discs were used for blank controK Group B ). Six beagle dogs received allograft intervertebral disc composites implantation of each group, respectively. Imageology examination were performed at 4, 8 and 12 weeks post-implantation. At 12 weeks after implantation, all dogs were sacrificed and the lumbar spines were harvested for the biomechanical analysis. Then the allografts were undergone histological analysis and ectogenic nucleus pulposus cell tracing. Results Bony fusion between allograft intervertebral disc and adjacent host intervertebral body were observed in all animal. The disc height and T2 signal intensity in Group A was better than that in Group B at 12 weeks follow-up. MRI showed typical degenerative changes in Group B. Biomechanical test showed a poor stability preservation in Group B compared to Group A. PKH-26 positive cells were identified within the allograft discs in Group A at 12 weeks, providing evidence of cell survival. Histological analysis showed the nucleus pulposus cell morphology, cell number and distribution of the allograft discs was better preserved in Group A compared to Group B at 12 weeks follow-up. Conclusion Nucleus pulposus cells intervention can effectively resist the degeneration of the allogenic transplanted intervertebral discs in a beagle model. This modified disc regeneration technique through nucleus pulposus cell injection or manipulation may have the potential to ensure the long term function preservation of allograft disc transplantation.%目的 观察组织工程技术的运用能否延缓椎间盘移植后的退行性改变.方法 将髓核细胞复合至同种异体椎间盘,体外培养后植入犬L4/L5椎间隙作为实验组(A组),对照组(B组)行同种异体椎间盘移植.使用影像学、生物力学及组织学分析评估植入椎间盘的转归并行组间比较.结果 移植椎间盘可与宿主椎体实现骨性融合.对照组椎间盘术后退变明显,12周时其椎间盘高度及髓核信号比灰度值明显低于实验组,稳定性丧失明显;组织学观察发现实验组移植椎间盘结构保持较好,髓核细胞数量较多,排列规则;对照组髓核形态保持欠佳,结构紊乱,髓核细胞数量减少,退行性改变明显.结论 通过复合种子细胞实现异体椎间盘的组织工程化可有效延缓椎间盘移植后的退行性改变.
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