闭合性胫骨骨折兔模型的建立与评估

Establishment and evaluation of rabbit model of closed tibial fracture

目的:探讨改良设计的三点弯曲骨折装置用于建立闭合性胫骨骨折兔模型的效果。方法:选取6月龄SPF级健康雄性新西兰兔40只,体质量2.5~3.0 kg,制备闭合性胫骨骨折兔模型,并于术后6周进行模型验证。预造模组5只,造模前未行临时外固定,后以改良设计三点弯曲骨折装置进行骨折;正式造模组35只,造模前行穿针及夹板外固定,后以改良设计三点弯曲骨折装置进行骨折。于术后2 h及4、6周行影像学、组织病理学评估骨折模型情况及愈合进程。结果:造模后2 h,预造模组呈不同程度的斜行骨折且断端明显移位;正式造模组除1只粉碎性骨折,2只弯曲蝶形骨折,2只未显示明显骨折线外,其余均呈简单横行及斜行骨折,断端无明显移位。根据判定标准,模型成功率为85.71%。造模后4周,实验兔固定针及夹板位置良好,骨折对位对线良好,骨折线已模糊不清,骨折端周围可见大量连续骨痂生长,骨痂密度较高。造模后6周,镜下见骨折处大量粗大的新生骨小梁,边缘成骨细胞附着并见少量巨噬细胞,膜内成骨区域为编织骨阶段,骨折处髓腔已部分再通,骨痂处于吸收塑性阶段,可见大量破骨细胞。X线显示骨折线几乎消失,髓腔部分已通,周围见外骨痂减少,骨痂处于塑形期,骨皮质连续。提示骨折模型呈二期愈合。结论:改良三点弯曲骨折装置可建立稳定的闭合性胫骨骨折兔模型,且操作简便,符合骨折愈合相关基础研究对闭合性骨折模型的要求。

Objective To explore the effect of a modified three-point bending fracture device for establishing a rabbit model of closed tibial fracture.Methods The model of closed tibial fracture was established in 406-month-old male New Zealand white rabbits with a body weight of 2.5 to 3.0 kg,and the model was verified at 6 weeks after operation.Five rabbits underwent pre modeling without temporary external fixation before modeling,and then were fractured with a modified three-point bending fracture device;35 rabbits underwent formal modeling.Before modeling,needles were inserted,and splints were fixed externally,and then the fracture was performed with a modified three-point bending fracture device.The fracture model and healing process were evaluated by imaging and histopathology at 2 hours,4 weeks,and 6 weeks after operation.Results Two hours after modeling,the prefabricated module showed oblique fracture in varying degrees and the broken end shifted significantly;Except for 1 comminuted fracture,2 curved butterfly fractures and 2 without obvious fracture line,the rest were simple transverse and oblique fractures without obvious displacement in formal modeling group.According to the judgment criteria,the success rate of the model was 85.71%.Four weeks after modeling,the fixed needle and splint of the experimental rabbits were in good position,the fracture alignment was good,the fracture line was blurred,many continuous callus growths could be seen around the fracture end,and the callus density was high.Six weeks after modeling,many thick new bone trabeculae at the fracture,marginal osteoblasts attached,and a small number of macrophages were seen under the microscope.The intramembrane osteogenesis area was in the preparation bone stage,the medullary cavity at the fracture had been partially reopened,the callus was in the absorption plastic stage,and many osteoclasts were visible.The X-ray showed that the fracture line almost disappeared,part of the medullary cavity had been opened,the external callus was reduced around,the callus was in the plastic stage,and the bone cortex was continuous.It suggests that the fracture model showed secondary healing.Conclusion The improved three-point bending fracture device can establish a stable rabbit model of closed tibial fracture,and the operation is simple,which meets the requirements of closed fracture model in basic research related to fracture healing.