活体小动物Micro-CT动态评价大鼠股骨牵张成骨  

Dynamic observation of ossification process in a rat femur distraction model by living small animal Micro-CT

作　　者：薛静[1] 彭江[1] 汪爱媛[1] 袁玫[1] 眭翔[1] 赵斌[1] 王玉[1] 范猛[1] 郭全义[1] 许文静[1] 卢世璧[1] 

机构地区：[1]解放军总医院全军骨科研究所、北京市复兴路28号,100853

出　　处：《中国矫形外科杂志》2010年第9期752-758,共7页Orthopedic Journal of China

基　　金：国家自然科学基金面上项目(编号:30872621);国家支撑计划(编号:2006BAI16B02)

摘　　要：[目的]利用活体小动物Micro-CT可连续观察大鼠股骨牵张成骨(distraction osteogenesis,DO)的优点,观察DO的不同时期骨愈合的模式,为寻找加速DO的愈合速度和带架方法提供指导。[方法]通过应用自行研制的大鼠股骨DO外固定架系统,对12只大鼠制备股骨DO模型,术后截骨端加压固定7d(静息期),第8d开始按0.25mm/12h的速度牵引延长共14d,延长7mm(延长期)。术后第21d延长结束后,用可透X线的高分子夹板材料替换金属外固定架,再固定35d(巩固期)。术后第28、42d分别处死2只大鼠用于组织学检查,其余8只大鼠分别于术后第21、28、42、56d麻醉后行X线及活体Micro-CT检查,并于术后56d取材,对其中5只行生物力学测试,余3只用于组织学检查。[结果]在DO静息期及延长期,延长区无明显新骨形成,延长区内主要为由纤维样组织组成的假性生长板结构。在巩固期前期(21d以内)主要为骨量的增加,表现为骨矿含量增加,骨小梁数量增多;巩固期21d以后,骨量仍持续增加,同时骨的质量也开始明显提高,表现为骨小梁增厚,已矿化组织矿化度提高。在术后56d(延长结束后5周)后,延长区内仍处于成骨和骨结构的改建中,假性生长板基本消失,未骨化的软骨组织依然存在。术后56d,DO侧股骨的最大扭矩及失效能量均小于健侧股骨。[结论]①在大鼠股骨DO延长结束后应用可透X线的高分子夹板固定牵引针可以获得稳定的固定;②改进大鼠股骨DO模型的固定方式后,Micro-CT可用于活体动态观察及评价其新骨形成;③长骨牵张成骨中骨量的增加自延长结束后开始,持续5周以上,骨质量的改建在延长结束后2～3周才开始,二者的发生具有时相性,提示相应的干预手段应在不同的时期进行;④对DO的全面观察应长于术后56d或延长结束后5周。[Objective]In order to dynamically observe the ossification process by living small animal Micro-CT in a rat femur distraction osteogenesis （DO） model,the author applied a special designed external fixiator system. [Methods]A femur DO model was made on 12 SD rats.After 7 days of latency,the femurs were distracted at a speed of 0.25 mm every 12 hours for 14 days.At the first day of consolidation period,the steel external fixiators were substituted by radio-transparent polymer splint material made fixiators.At 7 and 21 days of consolidation period,two randomly selected rats were sacrificed for histological examination.The other 8 rats were selected for X-ray and living Micro-CT examination at 0,7,21,35 days of consolidation period.All animals were sacrificed at 35 days of consolidation period,5 for biomechanical test,3 for histological examination.[Results]There was no significant new bone formed in distracted zone at latency and distraction periods.The volume of distracted zone increased little in the following 5 weeks of consolidation period.Bone volume,bone mineral content,bone volume fraction,and the number of trabeculae all increased over the consolidation period,while mineral content of mineralized tissue and thickness of traleculae did not increased until 3 weeks after consolidation began.At final observation （56 days post operation）,there still exist un-mineralized cartilage tissues in the central of distracted zone,and the distracted femurs had lower biomechanical property when compared with corresponding normal femurs.[Conclusion]1） Radio-transparent polymer splint is a satisfactory substitute of steel external fixator.2） Micro-CT is a useful tool for dynamical observing and evaluating bone formation status in DO model.3） The increasing of bone volume began at the end of distraction,lasting at least 5 weeks,while the remodeling of new formed bone began 3 weeks after distraction ended.The increasing and remodeling of new formed bone was not concord.This result indicates that,in order to obtai

关 键 词：牵张成骨 活体小动物Micro-CT 骨化 动态观察 

分 类 号：R687.3[医药卫生—骨科学]