丝素蛋白／羟基磷灰石组织工程化骨修复兔桡骨节段性骨缺损

Repairing radial segmental bone defects with tissue engineered bone of silk fibroin/hydroxyapatite in rabbits

目的 探讨丝素蛋白/羟基磷灰石（SF/HA）组织工程化骨的成骨作用,以期为临床治疗骨缺损提供新的人工骨材料.方法 将SF/HA与成骨诱导的兔骨髓基质干细胞（BMSCs）复合,构建组织工程化骨.取54只兔于左侧桡骨中上段制备15 mm节段性骨缺损.实验分3组（A、B组各24只,C组6只）：A组：植入SF/HA组织工程化骨,B组：单纯植入SF/HA;C组：骨缺损区不植入任何材料.于术后4、8、12及16周摄X线片,并于16周行螺旋CT扫描重建,观察骨缺损修复及骨塑形情况,参照Lane-Sandhu X线评分标准对各组骨缺损的骨修复程度评分.骨痂标本行 HE染色组织学观察,按照Lane-Sandhu组织学评分法比较12周和16周时各组的骨修复情况. 结果 术后16周,X线片示A组髓腔通畅,新骨塑形好,骨皮质连续;B组缺损区有缩小,两断端不连接;C组缺损区无明显骨痂生长.16周时螺旋CT扫描重建显示：A组骨塑形明显,骨缺损完全修复;B组有部分皮质骨形成,缺损区不能完全修复;C组骨缺损基本无修复.每组术后4、8、12、16周不同时间点的放射学评分差异均有统计学意义（P＜0.05）.术后12、16周时3组间Lane-Sandhu组织学评分差异均有统计学意义（P＜0.05）. 结论 SF/HA组织工程化骨具有良好的节段性骨缺损修复能力,但SF/HA本身缺乏骨诱导作用,单独修复节段性骨缺损作用有限.

Objective To explore the bone formation of silk fibroin/hydroxyapatite （SF/HA）co-cultured with bone marrow stromal cells （BMSCs） in rabbits. Methods The purified, culture-expanded and osteogenic BMSCs were combined with SF/HA in vitro to construct a tissue engineered bone. A segmental bone defect （15 mm in length） was created at each left radius in the rabbits which were randomized into 3 groups. The tissue engineered bone was implanted through open operation into the bone defects in Group 1. Group 2 was implanted with SF/HA scaffold alone, and Group 3 without any implant （unfilled）. Bone formation and moulding were observed by X-ray at 4, 8, 12 and 16 weeks and by spiral CT reconstruction at 16 weeks. Results The rate and quality of new bone formation were significantly different among Group 1, Group 2 and Group 3 by radiography and histological scores （ P 〈 0. 05）. The segmental bone defects were completely united in Group 1, but partially united in Group 2. There was no new bone formation and the defects were only repaired by fibrous tissue in Group 3. Conclusion SF/HA with BMSCs has a good ability of repairing segmental bone defects.