选择性激光烧结技术的多孔钛合金支架的骨组织工程学观察

Selective Laser Sintering-Produced porous titanium ahoy scaffold for bone tissue engineering

目的 探讨基于快速成型技术制作的多孔钛合金支架的体外细胞相容性及修复节段性骨缺损的疗效.方法 利用选择性激光烧结技术制作的多孔可控微结构的钛合金支架,同时使用酸蚀法对其表面进行改性,分为未处理支架组和酸蚀处理组;将小鼠前成骨细胞与两组支架进行复合培养,定期检测材料对细胞黏附、增殖和分化的影响;选取新西兰大白兔15只,制作桡骨中段骨缺损模型并植入支架,定期采用X线观察,并于术后12周取离体标本进行Micro-CT的骨体积分数测量及组织学观察.结果 支架两实验组支架上的细胞随着时间的延长（14 d）,ALP活性进行性增加（0.83±0.09比0.82±0.08,P＞0.05）;Micro-CT及组织学结果提示钛合金支架组孔内长入大量新生骨,与空白对照组相比差异有统计学意义[（25.4％±4.2％）比（23.6％ ±8.4％）比（12.3％±4.7％）,P＜0.05],但两实验组间差异无统计学意义[（25.4％±4.2％）比（23.6％ ±8.4％）,P＞0.05].结论 SLS制作的多孔钛合金支架展现了良好的体外相容性,能够有利于长段骨缺损的修复,不仅能够避免“应力遮挡”现象,且具有良好的骨传导性.

Objective To evaluate the biocompatibility of SLS-produced titanium alloy scaffold in vitro and investigate the therapeutic effects in repairing segmental bone defects.Methods Porous titanium alloy scaffolds were produced by SLS and their surfaces were either left untreated or acid etched.In vitro,mouse pre-osteoblasts （MC3T3-E1 cells） were cultured on these 2 group scaffolds,and then cell proliferation and differentiation were examined after cell seeding.In vivo,bone defects were artificially made in 15 New Zealand rabbits and the porous titanium specimens were implanted into the radius of rabbits for 3 months.The regulating checks of X-ray were determined.The osteointegration of the implants was investigated by Micro-CT and histological examination at 12 weeks after surgery.Results A gradual increase in cell-specific ALP synthesis by cells cultured in both groups was observed with longer culture time （14 d）.ALP activity did not differ significantly between two groups （0.834 ± 0.092 vs 0.815 ± 0.081,P 〉 0.05）.Both Micro-CT and the histological analysis indicated that the titanium alloy scaffolds had excellent ability to facilitate the osteointegration in vivo.The results were significantly different between the empty control and the 2 different surface modifications of SLS-implants （25.4% ± 4.2% vs 23.6% ± 8.4% vs 12.3% ± 4.7%,P 〈0.05）.Between the groups with implants,the number of bone points was not significantly different,irrespective of the surface treatment （25.4% ±4.2% vs 23.6% ±8.4%,P〉0.05）.Conclusion Selective Laser Sintering-Produced porous titanium alloy scaffold possessed admirable biocompatibility in vitro.It also could be contributed to the healing of long tulular bone defect.The porous Ti6Al4V implant not only reduced the stress-shielding but also exerted appropriate osteoconductive properties.