The effect of high voltage alternating electric field therapy on fracture healing / 中华物理医学与康复杂志

ABSTRACT

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 experimentsl 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 (RAP) 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 RAP 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 RAP caused by exposure to the high voltage alternating electric field.