Preventive Effect And Possible Mechanisms Of Ultrashort Wave Diathermy On Myogenic Contracture In A Rabbit Knee Extension Contracture Model

Objective: Joint contracture is one of the most common diseases in orthopedic rehabilitation.Joint contracture brings serious inconvenience to patients’ work and daily life,and impair their quality of life.However,the pathogenesis is unclear and treatments are limited.The objective of this study was to determine the preventive effect of ultrashort wave diathermy on immobilization-induced Myogenic contracture and explore the underlying mechanisms.Methods: Forty-two rabbits were randomly assigned into seven groups(n=6).According to the time of immobilization,the rabbits of Group I were further divided into one-week group(Group I-1),two-week group(Group I-2),four-week group(Group I-4).Groups U were treated with ultrashort wave diathermy during the immobilization,and according to the time of treatment,Group U were divided into one-week prevention group(Group U-1),two-week prevention group(Group U-2)and four-week prevention group(Group U-4).All intervention effects were assessed by evaluating the cross-sectional area(CSA),the knee-joint range of motion and the protein levels for Myogenic differentiation(Myo D)and Muscle atrophy F-box(MAFbx-1)of the rectus femoris.Results: In Group I and Group U,total contracture,myogenic contracture,Myo D and MAFbx-1 were significantly increased,and the CSA were significantly decreased(P<0.05 vs.Group C).Myo D were statistically significantly elevated in Group U,while MAFbx-1,CSA and myogenic contracture were significantly decreased(P<0.05 vs.Group I at each time point).Conclusion: In the early stages of the progression of rabbit knee joint contracture,ultrashort wave diathermy could reduce muscle atrophy and delay the process of muscle contracture during joint immobilization,the mechanisms of which may be explained as increased expression of Myo D triggered by suppressed MAFbx-1 mediated Ubiquitin-proteasome pathway.