血管化组织工程骨修复大鼠股骨缺损的实验研究

Prevascularization of tissue-engineered bone grafts promotes repair of femoral bone defects in rats

目的探讨血管化组织工程骨修复大鼠股骨缺损的效果。方法取20只10周龄健康SD雌性大鼠，制作大鼠左后肢股骨缺损模型。将20只大鼠随机分为2组（n=10）：A组骨缺损处植入组织工程骨，B组骨缺损处植入组织工程骨并行血管移植。分别于术后1周（n=3）、4周（／7,=3）、8周（n=3）取材，另1只备用，行放射学和组织学检测观察大鼠股骨缺损处新生骨生成和支架材料降解的情况。结果放射学结果显示：术后1周，A组与B组大鼠新生骨体积／总体积平均分别为5．47％±1．90％、8．49％±1．26％，差异无统计学意义（P〉0．05）；术后4、8周，A组大鼠新生骨体积／总体积（17．54％±2．04％、39．73％±4．01％）均显著低于B组大鼠（25．32％±2．15％、53．22％±2．94％），差异有统计学意义（P〈0．05）。术后1、4周，A组大鼠剩余支架体积／支架总体积平均分别为97．33％±2．52％、80．60％±4．00％，B组平均分别为95．67％±3．51％、75．22％±6．20％，两组间比较差异均无统计学意义（P〉0．05）；术后8周，A组大鼠剩余支架体积／支架总体积（65．46％±4．51％）显著高于B组大鼠（50．19％±4．91％），差异有统计学意义（P〈0．05）。组织学结果显示：术后8周，B组的材料与骨融合更为紧密，支架内部降解率高，成骨活性好。结论血管化组织工程骨能有效促进大鼠新生骨的形成，加速材料的降解，提高骨缺损的修复效果。

Objective To investigate the effect of prevascularized tissue-engineered bone graft on regeneration of femoral bone defects in rats. Methods Models of femoral bone defect were created at the bilateral hind limbs of 20 healthy female 10 week-old rats which were divided into 2 even groups randomly （ n = 10） . In group A, conventional tissue-engineered bone grafts were transplanted into the femoral bone defects; in group B, tissue-engineered bone grafts and vascular bundles were implanted into the femoral de- fects. At 1, 4 and 8 weeks after operation, 3 rats were sacrificed each time in each group to harvest samples. The remaining one in each group served as a spare animal. Regeneration of bone defects and degradation of scaffolds were assessed by radiologic modality and hematein eosin staining. Results At week 1, the new bone ratio （BV/TV） was 5.47% ± 1.90% in group A and 8.49% ± 1.26% in group B, showing no sig- nificant difference （P 〉 0.05）; at weeks 4 ＆ 8, the BV/TV were 17.54% ±2.04% and 39.73%±4.01% in group A, significantly lower than those in group B （25.32% ± 2. 15% and 53.22% ± 2.94% ） （ P 〈 0. 05） . At weeks 1 ＆ 4, the scaffold degradation ratios （RSV/SV） were 97.33% ± 2.52% and 80.60% ±4.00% , showing no significant differences from those in group B （95.67% ±3.51% and 75.22% ± 6. 20% ） （ P 〉 0. 05 ）. At week 8, the scaffold degradation ratio in group A （65.46% ± 4. 51% ） was significantly higher than that in group B （50. 19% ± 4. 91% ） （P 〈 0. 05）. At week 8, hematein eosinstaining showed better integration of scaffolds with the femur, faster degradation of the interior scaffolds and greater osteogenetic activity in group B. Conclusion Prevascularization of tissue-engineered bone graft may increase new bone volume and scaffold degradation rate, promoting repair of femoral bone defects in rats.