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目的:探讨同种异体椎间盘复合髓核细胞移植的转归,观察转人端粒酶逆转录酶(human telomerasereverse transcriptase,hTERT)基因髓核细胞介入椎间盘移植的生物学效应。方法:常规分离8周龄比格犬髓核细胞,将PKH-26标记的传2代髓核细胞(NPc)和转hTERT基因髓核细胞(hTERT-NPc)分别注射入冷冻保存的同种异体椎间盘内构建组织工程化同种异体椎间盘。选择12月龄同种犬18只随机分为3组,分别植入hTERT-NPc组织工程化的同种异体椎间盘(A组)、NPc组织工程化的同种异体椎间盘(B组)以及未组织工程化的同种异体椎间盘(C组)。每只犬于术后4、8、12周行正侧位X线片及MRI检查,观察移植椎间盘同宿主椎体愈合情况、移植椎间盘高度和信号变化情况;手术后12周麻醉状态下处死实验动物取L1~L7段脊柱标本进行生物力学测试,取移植椎间盘进行组织学观察。结果:X线及MRI检查结果显示3组移植椎间盘与宿主椎体均实现了良好的骨性融合,其中C组椎间盘术后出现了呈进展趋势的退行性改变,至移植后12周,其椎间盘高度及髓核信号比灰度值明显低于A、B两组(P<0.05)。生物力学显示术后12周时,C组移植椎间盘在屈伸和旋转方向的活动度显著性大于A、B两组(P<0.05),A组与B组无显著性差异(P>0.05)。激光共聚焦显微镜观察到A、B组移植椎间盘髓核区域内有红色荧光细胞;光学显微镜下观察A、B两组移植椎间盘结构保持较好,外形类似软骨细胞的髓核细胞数量较多,排列较为规则;C组髓核形态保持欠佳,结构较为紊乱,髓核细胞数量明显减少,细胞形态欠饱满,退行性改变明显。RT-PCR分析显示术后12周时A组髓核内可检测到hTERTmRNA的阳性表达。结论:犬同种异体椎间盘移植后可在宿主体内存活,通过复合NPc可延缓椎间盘移植后的退行性改变;hTERT-NPc介入具有更好的保持异体椎间盘功能的潜力,有望保证同种异体椎间盘移植的远期疗效。
OBJECTIVE: To investigate the outcome of allogeneic intervertebral disc nucleus pulposus transplantation and to investigate the biological effect of human telomerase reverse transcriptase (hTERT) gene intervertebral disc transplantation. Methods: The nucleus pulposus cells of 8-week-old beagle dogs were routinely isolated. PKH-26-labeled second passage nucleus pulposus cells (NPc) and hTERT-derived nucleus pulposus cells (hTERT-NPc) were injected into cryopreserved allogeneic Tissue engineered allogeneic disc was constructed in the disc. Eighteen 18-month-old dogs were randomly divided into 3 groups: hTERT-NPc tissue-engineered allograft intervertebral disc (group A), NPc tissue-engineered allograft disc (group B) Engineered Allograft Discs (Group C). At 4, 8 and 12 weeks after operation, each dog was examined by lateral X-ray and MRI examinations to observe the healing status of the intervertebral disc with the same host vertebra, the height of the intervertebral disc and signal changes. After 12 weeks of operation, the experimental animals were killed under anesthesia The biomechanical tests were performed on the L1 ~ L7 spinal specimens and the intervertebral discs were taken for histological observation. Results: The results of X-ray and MRI showed that the three groups of transplanted intervertebral discs and host vertebrae both achieved good osteosynthesis. The degenerative changes showed a trend of progression after C disc surgery. At 12 weeks after transplantation, the intervertebral disc Height and nucleus pulposus signal than the gray value was significantly lower than A, B two groups (P <0.05). Biomechanics showed that at 12 weeks postoperatively, the mobility of intervertebral discs in C group was significantly greater than those in A and B groups (P <0.05). There was no significant difference between A group and B group (P> 0.05). Laser confocal microscopy showed red fluorescent cells in the nucleus pulposus nucleus of group A and group B. Under light microscope, the structure of intervertebral disc in group A and B remained well, and the number of nucleus pulposus cells with similar shape was larger The rules of nucleus pulposus in group C were not well maintained, the structure was disorganized, the number of nucleus pulposus cells was significantly reduced, the cell morphology was under full, and the degenerative changes were obvious. RT-PCR analysis showed that the positive expression of hTERT mRNA was detected in the nucleus pulposus of group A at 12 weeks after operation. CONCLUSIONS: Allogeneic intervertebral disc can survive in the host, which can delay the degenerative changes after intervertebral disc transplantation through compound NPc. The hTERT-NPc intervention has the potential to maintain the function of allogeneic disc, and is expected to ensure the allograft intervertebral disc transplantation Long-term efficacy.