骨折断端的微动与小鼠胫骨骨折愈合方向的影响关系研究

Study on the Relationship between Micromotion of Fracture Ends and the Direction of Tibial Fracture Healing in Mice

目的:探究骨折断端的微动与小鼠胫骨骨折愈合方向的影响关系。方法:将18只C57BL/6小鼠分为假手术对照组(A组)、不稳定固定组(B组)及稳定固定组(C组),每组各6只,其中B、C组制作胫骨骨折模型,A组不做骨折处理,于术后7 d、14 d及21 d对三组进行X线摄影、染色及PCR基因检测,以观察骨折断端髓内针固定情况、骨折线情况、骨痂生长情况、骨与软骨细胞的生长比例的差异及成骨标志性基因ALP、Runx2和软骨形成标志性基因Aggrecan、Sox-9分布比例的不同。结果:X线扫描发现,B组:骨折处髓内针插入情况良好,术后7 d、14 d及21 d小鼠骨痂形成少且缓慢,骨折线2周内始终较为清晰,3周后稍模糊;C组:骨折处髓内针插入情况良好,术后7 d、14 d及21 d小鼠钙化骨痂形成较快且多,骨折线模糊;A组为假手术对照组。染色及PCR基因检测分析发现,B组第7 d~21 d极少量骨组织被染成红色,而软骨呈条状被染成蓝色,软骨逐步形成出现,软骨细胞的标志性基因显著升高,而成骨细胞的标志性基因略有升高,骨总体呈现出以软骨成骨完成骨折愈合的表现;C组第7 d~21 d骨组织被多染成红色,极少量为蓝色,成骨细胞的标志性基因显著增高,而成软骨细胞的标志性基因略有升高,可见总体呈现出以成骨细胞增长的骨膜内成骨而进行骨折愈合的表现;A组为假手术对照组。结论:骨折断端较低的机械应力可以促进骨折愈合更多地向成骨细胞增长的骨膜内成骨方向演进,这可有效减少骨折不愈合与延迟愈合的发生。

Objective: To explore the relationship between the micro movement of the fractured end and the direction of tibial fracture healing. Methods: We divided 18 C57BL/6 mice into three groups: sham operation control group (group A), unstable fixation group (group B) and stable fixation group (Group C), with six mice in each group. The tibial fracture models were made in groups B and C, while the fracture treatment was not made in group A. X-ray photography, staining and PCR gene detection were performed on the 7th, 14th and 21st days after operation in the three groups to ob-serve the fixation of intramedullary nail at the fracture end, fracture line, callus growth, growth ra-tio difference between bone and chondrocytes, and distribution ratio difference between osteogenic marker genes ALP, Runx2 and chondrogenic marker genes aggrecan and Sox-9. Results: In group B, X-ray scanning showed that the insertion of intramedullary needle at the fracture was good, and the callus formation of mice was less as well as slow on the 7th, 14th and 21st days after operation, and the fracture line was always clear within 2 weeks and slightly blurred after 3 weeks. In Group C, X-ray scanning showed that the insertion of intramedullary needle at the fracture was good as well as and the calcified callus of mice formed rapidly and more, and the fracture line was blurred on the 7th, 14th and 21st days after operation. Group A was sham operated control group. In terms of the staining and gene detection analysis, in group B, from the 7th day to the 21st day, a very small amount of bone tissue was stained red, while cartilage was stained blue in strips, and cartilage gradually formed. The marker genes of chondrocytes were significantly increased, while the marker genes of osteoblasts were slightly increased, and bone showed the performance of complete fracture healing with cartilage osteogenesis. In group C, from the 7th day to the 21st day, the bone tissue was mostly stained red, and a very small amount was blue. The marker genes of osteoblasts were signif-icantly increased, while the marker genes of chondroblasts were slightly increased. It can be seen that the overall performance of fracture healing was based on the periosteal osteogenesis of osteo-blasts;Group A was sham operated control group. Conclusion: Lower mechanical stress of fracture can promote fracture healing to evolve towards the direction of osteogenesis in periosteum where osteoblasts grow, which can reduce the risk of fracture nonunion and delayed healing.