BACKGROUND: Repair of bone defects is not only a clinical problem, but also a hot topic in the field of orthopedics. Although autologous bone grafting is considered as the "gold standard" for bone repair, its use is limited due to the limited source of autogenous bone, bone infections and pains that are easy to occur in the donor region. Allograft bones are always associated with immune rejection, slow healing, and infection. Therefore, it is imminent to develop new materials for bone repair. OBJECTIVE: To explore the effect of rabbit adipose-derived stem cells (rADSCs) as seed cells and hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) composite as a carrier on the repair of rabbit vertebral defects. METHODS:Thirty-eight 3-month-old New Zealand white rabbits were selected,and two of them were used to culture rADSCs in vitro. Passage 3 rADSCc were inoculated on HA/β-TCP scaffolds and then cultured in vitro for 2 weeks.A 5 mm×5 mm×3 mm bone defect was prepared at the anterior edge of L4/5vertebral body in the remaining 36 rabbits. These model rabbits were then randomized into cell-scaffold composite group, scaffold group and control group with no intervention, with 12 rabbits in each group. rADSCs/HA/β-TCP composite and HA/β-TCP scaffold were implanted into the cell-scaffold and HA/β-TCP groups, respectively. Anteroposterior and lateral DR of the spine and Lane-Sandhu X-ray were performed at 4, 8, 12 postoperative weeks. All rabbits were sacrificed at 12 postoperative weeks and specimens were collected for gross and histopathological observations. RESULTS AND CONCLUSION: Under the gross observation, bone defects in the cell-scaffold group were essentially replaced by new bone tissues, which was significantly better than that in the scaffold group and control group. At 12 postoperative weeks, the material implanted was basically absorbed in the cell-scaffold group, partially absorbed in the scaffold group and poorly absorbed in the control group in which there was a clear boundary with the surrounding tissues and patchy calcified shadows were visible. X-ray results showed that the repair effect in the cell-scaffold group was better than that in the scaffold group and control group (P < 0.05). Histopathological findings showed the marked absorption of the implant in the cell-scaffold group, partial residual in the scaffold group with some fibrous calluses and osteoid tissues, and a large amount of fiber tissues and a small amount of calluses in the control group. Overall, the rADSCs/HA/β-TCA has a good ability to repair bone defects.%背景:骨缺损的修复不仅是临床上的难题,也一直是骨科领域的热点.虽然自体骨移植是骨修复技术的"金标准",但由于自体骨来源有限,易出现取骨区感染、疼痛等症状,而且同种异体骨有免疫排斥、愈合缓慢、感染等特点,因此研发新型骨缺埙修复材料迫在眉睫.目的:评价兔脂肪干细胞与羟基磷灰石/β-磷酸三钙骨组织工程复合体修复兔椎体缺损的效果.方法:取3月龄新西兰大白兔38只,其中2只用于体外培养脂肪干细胞,将第3代经成骨诱导分化的兔脂肪干细胞接种于羟基磷灰石/β-磷酸三钙支架上进行体外培养2周.36只新西兰大白兔随机分为3组(n=12),均在L4/5椎体前缘制备一直径约5 mm、深约3 mm椎体缺损,A组、B组分别植入兔脂肪干细胞/羟基磷灰石/β-磷酸三钙复合体、羟基磷灰石/β-磷酸三钙支架,C组不植入材料.术后4,8,12周行脊柱正侧位DR照射,进行Lane-Sandhu X射线评分,术后12周处死取标本,行大体观察、组织病理学观察椎体缺损修复情况.结果与结论:①大体观察发现A组椎体缺损区基本被新生骨组织取代,修复效果明显优于B组及C组;②术后12周时,A组椎体缺损区材料基本吸收,B组椎体缺损材料部分吸收,可见骨痂形成,C组椎体缺损区边界尚清晰,可见片状钙化影.经Lane-Sandhu X射线评分后统计学分析,A组椎体缺损修复情况明显优于B组及C组(P < 0.05);③组织病理学观察发现A组材料吸收明显,B组部分材料残留,仅见到部分纤维性骨痂及少许类骨样组织形成,C 组可见大量纤维组织及少许骨痂形成;④以上结果表明,脂肪干细胞与羟基磷灰石/β-磷酸三钙构建的骨组织工程复合体具有较好的修复椎体缺损的能力.
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