硫酸钙人工骨/骨髓间充质干细胞构建组织工程化骨诱导脊柱融合

Construction of calcium sulfate/bone marrow mesenchymal stem cells tissue-engineered bone for spinal fusion

背景:硫酸钙具有良好的组织相容性和可降解性,是一种安全有效的骨移植替代物。目的:观察医用硫酸钙人工骨与兔骨髓间充质干细胞复合的成骨作用。方法:取36只新西兰大白兔,行腰椎后路L4/5椎间盘摘除后,随机均分为3组,自体骨组在椎间隙植入自体髂骨,异种骨组在椎间隙植入异体脱钙小牛骨,组织工程骨组椎间隙植入医用硫酸钙人工骨与同种异体骨髓间充质干细胞复合物。植入后4,8,16周摄腰椎正侧位X射线片,观察椎体间植骨愈合及塑形情况;留取骨痂标本行组织学观察椎间植骨愈合程度;于16周对脊柱融合部位进行生物力学分析。结果与结论:植入16周时,自体骨组椎间骨小梁连续,椎间融合基本完成,大量编织骨相互融合成片;异种骨组椎间隙形成不完全骨性融合,软骨组织大部分分化为骨组织,但中间仍为纤维组织;组织工程骨组椎间骨小梁连续,椎间融合基本完成,大量编织骨相互融合成片,人工骨基本吸收、骨化,仅有少部分残留;自体骨组、组织工程骨组失效强度和刚度均优于异种骨组(P<0.05)。提示医用硫酸钙人工骨/骨髓间充质干细胞构建的组织工程骨具有具有良好的成骨和骨诱导作用,可以较好地促进脊柱椎体间融合。

BACKGROUND：Calcium sulfate has good biocompatibility and biodegradability, which is a safe and effective bone graft substitute. OBJECTIVE：To investigate the osteogenesis ability of calcium sulfate combined with bone marrow mesenchymal stem cells. METHODS：After L4/5 posterior lumbar discectomy, 36 rabbits were randomized into three groups：rabbits in autologous bone group were implanted with autologous iliac bone via the intervertebral space;animals in al ogenic bone group were implanted with decalcified bovine bone;rabbits in tissue-engineered bone group were implanted with calcium sulfate combined with bone marrow mesenchymal stem cells. Bone formation and molding were observed by gross observation, anteroposterior and lateral X-ray, histology and biomechanics at 4, 8 and 16 weeks. Cal us specimens were employed for histological observation of interbody fusion. Biomechanical analysis of spinal fusion site was conducted at 16 weeks. RESULTS AND CONCLUSION：Sixteen weeks later, interbody fusion was complete in the autologous bone group, the trabecular bone bridged continuously and a large amount of woven bone was merged into pieces;in the al ogenic bone group, incomplete bony fusion was found between the intervertebral space, most of cartilage tissues differentiated into bone, but fibrous tissue was also ful of the central part;in the tissue-engineered bone group, interbody fusion was complete, and a large amount of woven bone was fused into pieces, while the artificial bone was absorbed and ossified with smal residual. Failure strength and stiffness in the autologous bone and tissue-engineered bone groups were superior to those in the al ogenic bone group. These findings indicate that the calcium sulfate/bone marrow mesenchymal stem cells tissue-engineered bone has excellent osteogenic and osteoinductive capacity that can exert a good function of promoting spinal interbody fusion.