Octacalcium Phosphate/Gelatin Composite (OCP/Gel) Enhances Bone Repair in a Critical-sized Transcortical Femoral Defect Rat Model
Octacalcium Phosphate/Gelatin Composite (OCP/Gel) Enhances Bone Repair in a Critical-sized Transcortical Femoral Defect Rat Model
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DOI：
10.1097/corr.0000000000002257
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发表时间：
2022-10-01
影响因子：
4.2
通讯作者：
Suzuki, Osamu
中科院分区：
文献类型：
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作者：
Hamada, Soshi;Mori, Yu;Suzuki, Osamu
背景植骨广泛用于治疗大面积骨缺损。生物活性磷酸八钙材料与明胶海绵（OCP/凝胶）的多孔复合材料已被证明可迅速生物降解，并在膜性骨缺损和长骨缺损的动物模型中被新骨替代。然而，目前还不清楚OCP/Gel是否可以在更严重的骨缺损中再生骨，例如临界尺寸的经皮质骨缺损。问题/目的使用标准化的、经皮质的、临界尺寸骨缺损的体内大鼠股骨模型，我们问：通过（1）显微CT评价，（2）组织学和组织形态测量，（3）骨钙素染色和抗酒石酸酸性磷酸酶染色。方法使用34只12周龄雄性Sprague-Dawley大鼠（体重356 ± 25.6 g）。在实验室制备了凝胶和OCP/凝胶复合材料。由两种材料制造直径为3 mm、高度为4 mm的多孔圆柱体。将OCP/凝胶和凝胶圆柱体植入左侧大鼠股骨中直径为3 mm的经皮质临界尺寸骨缺损模型中。随机分配OCP/凝胶和凝胶，并植入圆柱体。对缺损区的生物学反应进行了放射学和组织学评价。植入后4周和8周，进行CT评估、脱钙样品的组织学检查和免疫组织化学染色，以定量评估新骨形成和剩余骨移植替代物以及成骨细胞和破骨细胞样细胞的活性（n = 24）。在植入后3周对未脱钙样本进行定性组织学评价（n = 10）。CT和脱钙组织分析不进行盲法，但分析undecalcified标本进行盲conditions.Results放射学分析显示，OCP/凝胶组显示不透射线的区域周围的OCP颗粒和边缘的缺陷边缘植入后4周，表明新骨形成发生在两种方式。相比之下，凝胶组中的大鼠股骨在缺损区域的边缘处具有有限的不透射线区。在植入后4周和8周，OCP/Gel组通过显微CT分析的新骨体积量高于Gel组（植入后4周：OCP/凝胶与凝胶：6.1 +/- 1.6 mm（3）与3.4 +/- 0.7 mm（3），平均差异2.7 [95%置信区间（CI）0.9至4.5]; p = 0.002;组内相关系数[ICC] 0.72 [95% CI 0.29 - 0.91];植入后8周：OCP/凝胶与凝胶：3.9 +/- 0.7 mm（3）与1.4 +/- 1.1 mm（3），平均差异2.5 [95% CI 0.8 - 4.3]; p = 0.004; ICC 0.81 [95% CI 0.47至0.94]）。组织学评价还显示，在植入后4周和8周，OCP/Gel组的新骨形成百分比较高（植入后4周：OCP/凝胶对比凝胶：31.2% +/- 5.3%对比13.6% +/-4.0%，平均差异17.6% [95% CI 14.2%至29.2%]; p < 0.001; ICC 0.83 [95% CI 0.53 - 0.95];植入后8周：OCP/凝胶与凝胶：28.3% +/- 6.2% vs 9.5% +/-1.9%，平均差异18.8% [95% CI 11.3%-26.3%]; p < 0.001; ICC 0.90 [95% CI 0.69 - 0.97]）。在植入后4周，OCP/凝胶组中缺损区域的桥接开始早于凝胶组。骨钙素免疫组化显示，4周时，OCP/Gel组成熟成骨细胞数量高于Gel组（OCP/凝胶对比凝胶：42.1 +/- 6.5/mm（2）对比17.4 +/- 5.4/mm（2），平均差异24.7 [95% CI 16.2 - 33.2]; p < 0.001; ICC 0.99 [95% CI 0.97至0.99]）。4周时，OCP/Gel复合材料组破骨细胞样细胞数高于Gel组（OCP/凝胶对比凝胶：3.2 +/- 0.6/mm（2）对比0.9 +/- 0.4/mm（2），平均差异2.3 [95% CI 1.3 - 3.5]; p < 0.001;结论OCP/Gel复合材料可诱导大鼠股骨临界大小经皮质骨缺损的早期骨重建和皮质骨修复，其时间短于Gel对照组，提示OCP/Gel可作为骨替代材料治疗严重骨缺损。
Background Bone grafting is widely used to treat large bone defects. A porous composite of a bioactive octacalcium phosphate material with gelatin sponge (OCP/Gel) has been shown to biodegrade promptly and be replaced with new bone both in animal models of a membranous bone defect and a long bone defect. However, it is unclear whether OCP/Gel can regenerate bone in more severe bone defects, such as a critical-size transcortical defect.Questions/purposes Using an in vivo rat femur model of a standardized, transcortical, critical-size bone defect, we asked: Compared with a Gel control, does OCP/Gel result in more newly formed bone as determined by (1) micro-CT evaluation, (2) histologic and histomorphometric measures, and (3) osteocalcin staining and tartrate-resistant acid phosphatase staining?Methods Thirty-four 12-week-old male Sprague-Dawley rats (weight 356 +/- 25.6 g) were used. Gel and OCP/Gel composites were prepared in our laboratory. Porous cylinders 3 mm in diameter and 4 mm in height were manufactured from both materials. The OCP/Gel and Gel cylinders were implanted into a 3-mm-diameter transcortical critical-size bone defect model in the left rat femur. The OCP/Gel and Gel were randomly assigned, and the cylinders were implanted. The biological responses of the defect regions were evaluated radiologically and histologically. At 4 and 8 weeks after implantation, CT evaluation, histological examination of decalcified samples, and immunostaining were quantitatively performed to evaluate new bone formation and remaining bone graft substitutes and activity of osteoblasts and osteoclast-like cells (n = 24). Qualitative histological evaluation was performed on undecalcified samples at 3 weeks postimplantation (n = 10). CT and decalcified tissue analysis was not performed blinded, but an analysis of undecalcified specimens was performed under blinded conditions.Results Radiologic analysis revealed that the OCP/Gel group showed radiopaque regions around the OCP granules and at the edge of the defect margin 4 weeks after implantation, suggesting that new bone formation occurred in two ways. In contrast, the rat femurs in the Gel group had a limited radiopaque zone at the edge of the defect region. The amount of new bone volume analyzed by micro-CT was higher in the OCP/Gel group than in the Gel group at 4 and 8 weeks after implantation ( 4 weeks after implantation: OCP/Gel versus Gel: 6.1 +/- 1.6 mm(3) versus 3.4 +/- 0.7 mm(3), mean difference 2.7 [95% confidence interval (CI) 0.9 to 4.5]; p = 0.002; intraclass correlation coefficient [ICC] 0.72 [95% CI 0.29 to 0.91]; 8 weeks after implantation: OCP/Gel versus Gel: 3.9 +/- 0.7 mm(3) versus 1.4 +/- 1.1 mm(3), mean difference 2.5 [95% CI 0.8 to 4.3]; p = 0.004; ICC 0.81 [95% CI 0.47 to 0.94]). Histologic evaluation also showed there was a higher percentage of new bone formation in the OCP/Gel group at 4 and 8 weeks after implantation ( 4 weeks after implantation: OCP/Gel versus Gel: 31.2% +/- 5.3% versus 13.6% +/- 4.0%, mean difference 17.6% [95% CI 14.2% to 29.2%]; p < 0.001; ICC 0.83 [95% CI 0.53 to 0.95]; 8 weeks after implantation: OCP/Gel versus Gel: 28.3% +/- 6.2% versus 9.5% +/- 1.9%, mean difference 18.8% [95% CI 11.3% to 26.3%]; p < 0.001; ICC 0.90 [95% CI 0.69 to 0.97]). Bridging of the defect area started earlier in the OCP/Gel group than in the Gel group at 4 weeks after implantation. Osteocalcin immunostaining showed that the number of mature osteoblasts was higher in the OCP/Gel group than in the Gel group at 4 weeks (OCP/Gel versus Gel: 42.1 +/- 6.5/mm(2) versus 17.4 +/- 5.4/mm(2), mean difference 24.7 [95% CI 16.2 to 33.2]; p < 0.001; ICC 0.99 [95% CI 0.97 to 0.99]). At 4 weeks, the number of osteoclast-like cells was higher in the OCP/Gel composite group than in the Gel group (OCP/Gel versus Gel: 3.2 +/- 0.6/mm(2) versus 0.9 +/- 0.4/mm(2), mean difference 2.3 [95% CI 1.3 to 3.5]; p < 0.001; ICC 0.79 [95% CI 0.35 to 0.94]).Conclusion OCP/Gel composites induced early bone remodeling and cortical bone repair in less time than did the Gel control in a rat critical-size, transcortical femoral defect, suggesting that OCP/Gel could be used as a bone replacement material to treat severe bone defects.