高压交变电场治疗对大鼠骨折愈合的影响

The effect of high voltage alternating electric field therapy on fracture healing

目的探讨高压交变电场治疗对大鼠骨折愈合的影响。方法共选取sD大鼠48只，将其制成胫骨近侧皮质骨缺损模型，采用随机数字表法将制模成功的41只大鼠分为实验组（21只）与对照组（20只）。实验组每日接受高压交变电场治疗，对照组仅给予假刺激。于制模后第7、14、21、28天时各组分别取5只大鼠（实验组于制模后第14天时取6只）采血并检测血清骨钙素（OC）及骨性碱性磷酸酶（BAP）含量，随后处死大鼠并提取手术侧整根胫骨检测骨折处骨痂骨密度值（BMD）；同时截取含骨折部位的1cm胫骨组织进行组织学观察。结果实验组大鼠在制模后第14、28天时骨折部位BMD均显著高于对照组（P〈0．05）；血清学检测显示制模后第14、21、28天时实验组大鼠血清OC含量均显著高于对照组（P〈0．05），制模后第14、28天时实验组BAP含量亦明显高于对照组（P〈0．05）；HE染色显示，在骨折愈合早期阶段（如制模后7-14d），实验组骨折部位血肿机化、吸收均早于对照组，成软骨细胞、成骨细胞提早出现而且数量较多；在骨折愈合晚期（如制模后21-28d）阶段，实验组骨小梁融合及矿化均早于对照组。结论高压交变电场治疗能促进骨折部位血肿机化、吸收，促进骨祖细胞增殖与分化，加强成骨细胞、软骨细胞增殖并合成细胞外基质，从而加速骨折愈合，其治疗机制可能与促进骨折部位OC及BAP表达有关。

Objective To explore the effect of high voltage alternating electric field therapy on fracture healing in rats. Methods An animal model of cortical bone defect was successfully established in the unilateral proximal tibia of 41 rats. They were then randomized into an experimental group （21 rats） and a control group （20 rats）. The animals in the experimental group were given high voltage alternating electric field therapy for 30 minutes daily, while those in the control group only had sham exposure to the high voltage alternating electric field therapy. Rats in each group were sacrificed at days 7, 14, 21 and 28 post-operation. After blood collection, the operated tibias of the rats were resected with muscle and other soft tissue removed. Bone mineral density （BMD） of the callus at the fracture point was measured using dual energy X-ray absorptiometry （DEXA）. The calluses were then cut down and fixed, decalcificated and sliced for histological observation. At the same time serum osteocalcin （OC） and bone alkaline phosphatase （BAP） were also detected by ABC-ELISA. Results The BMD examination showed that callus BMD in the experimental group was significantly higher than in the control group at days 14 and 28. Serum OC and BAP in the experimental group were also higher at days 14 day 21, and OC was still significantly higher in the experimental group at day 28. Histological examination showed that in the early stages of bone healing hematoma absorption and organization appeared earlier in the experimental group than in the control group, with remarkable osteoblast and chondroblast proliferation. While at the later stage, bone trabeculas connection and mineralization also appeared earlier in the experimental group than in the control group. Conclusions High voltage alternating electric field therapy may promote fracture healing by accelerating hematoma absorption and organization, elevating osteoblast proliferation and differentiation as well as promoting extracellular matrix secretion and mineralization. The underlying therapeutic mechanism might be related to the increased expression of OC and BAP caused by exposure to the high voltage alternating electric field.