摘要
目的 探讨大鼠牵拉成骨(DO)模型中矿化期何时拆除外固定延长器而无延长区回缩.方法 取42只12周龄雄性SD大鼠,随机分为6组(n=7):A组、B组、C组、D组、E组及F组,分别在矿化期第1、2、3、4、5、6周拆除外固定延长器.建立DO模型:在大鼠左侧股骨水平垂直置入4枚螺纹针,中段截骨后安装外固定延长器,髓腔置入1枚克氏针;潜伏期(5 d)结束后延长14d,共延长7.0 mm.每组随机抽取3只大鼠处死,延长区脱钙后行苏木精-伊红(HE)染色;其余4只在拆除外固定延长器前和拆除外固定延长器5周后摄X线片.比较各组大鼠的HE染色结果、初始延长区长度及延长区回缩长度等.结果 HE染色结果:A组延长区可见大片纤维组织及少量幼稚小血管;B组延长区出现少量肥大软骨细胞,可见纤维性连接;C组延长区可见部分软骨细胞、骨细胞及纤维组织;D组延长区两侧出现大量软骨细胞,中心仍可见纤维组织连接;E组延长区成熟肥大软骨细胞较前减少,可见部分骨髓;F组延长区可见少量软骨细胞,髓腔部分再通,内有骨髓.A组、B组、C组、D组、E组及F 组大鼠初始延长区长度分别为(6.98±0.14)、(7.02±0.18)、(7.02±0.08)、(7.02±0.11)、(7.01±0.18)、(7.00±0.12)mm,差异无统计学意义(P＞0.05).A组、B组大鼠延长区回缩长度[(4.34±0.78)、(3.45±0.57)mm]显著大于 D 组、E 组、F 组大鼠[(0.16±0.17)、(-0.02±0.14)、(0.03±0.82)mm],差异均有统计学意义(P＜0.05).拆除外固定延长器而无延长区回缩的时间为矿化期第4周(D组),D组愈合指数为87d/cm,无回缩指数为67 d/cm.结论 在大鼠DO模型中,矿化期第4周及以后拆除外固定延长器,无延长区回缩.
Abstract
Objective To explore the timing for removal of the external fixator without retraction of elonga-tion zone during the mineralization stage in SD rat models of distraction osteogenesis(DO).Methods Forty-two 12-week-old male Sprague-Dawley rats were randomly divided into 6 groups(groups A to F,n=7).The exter-nal fixator was removed at 1 to 6 weeks during the mineralization stage in groups A to F,respectively.To estab-lish SD rat models of DO,after 4 threaded needles were inserted into the left femur horizontally and vertically,an external fixator was installed after osteotomy.A Kirschner wire was next inserted into the medullary cavity.After the incubation period(5 days),bone elongation lasted for 14 days until 7.0 mm was extended.Three rats were randomly selected from each group and sacrificed.After decalcification of the elongation zone,histological hematoxylin-eosin staining was performed.Radiographs were taken before removal of the external fixator and 5 weeks after removal of the external fixator for the remaining 4 rats in each group.The HE staining results,length of initial elongation zone,and retraction length of elongation zone were compared between groups.Results HE staining showed large patches of fibrous tissue and a few immature small blood vessels in the elongation zone in group A,a small number of hypertrophic chondrocytes and fibrous junctions in the elongation zone in group B,some chondrocytes,osteocytes and fibrous tissue in the elongation zone in group C,a large number of chondrocytes on both sides of the elongation zone and fibrous connection in the center of the elongation zone in group D,a decreased number of mature hypertrophic chondrocytes and partial bone marrow in the elonga-tion zone in group E,and a small number of chondrocytes and a partially recanalized medullary cavity with bone marrow in the elongation zone in group F.The lengths of initial elongation zone in groups A,B,C,D,E and F were,respectively,(6.98±0.14)mm,(7.02±0.18)mm,(7.02±0.08)mm,(7.02±0.11)mm,(7.01±0.18)mm and(7.00±0.12)mm,showing no statistically significant differences(P＞0.05).The lengths of retraction of elongation zone in groups A and B[(4.34±0.78)mm and(3.45±0.57)mm]were significantly longer than those in groups D,E and F[(0.16±0.17)mm,(-0.02±0.14)mm,and(0.03±0.82)mm](P＜0.05).The timing for removal of the external fixator without retraction of elon-gation zone was the 4th week during the mineralization stage(group D);the healing index was 87 d/cm and the non-retraction index 67 d/cm in group D.Conclusion In the SD rat models of DO,removal of the external fixator at 4 weeks and later during the mineralization stage may not lead to retraction of the elongation zone.
维普
万方数据