Preventive effect and possible mechanisms of ultrashort wave diathermy on myogenic contracture in a rabbit model

Abstract

The purpose of this study was to determine the preventive effect of ultrashort wave diathermy on immobilization-induced myogenic contracture and to explore its underlying mechanisms. Forty-two rabbits were randomly assigned into control (Group C), immobilization (Group I, which was further divided into one week, Group I-1; two weeks, Group I-2; and four weeks, Group I-4, subgroups by the length of immobilization) and ultrashort wave prevention (Group U, which was further divided into one week, Group U-1; two weeks, Group U-2; and four weeks, Group U-4, by time of treatment) groups. Intervention effects were assessed by evaluating rectus femoris cross-sectional area (CSA), knee range of motion, and the protein levels for myogenic differentiation (MyoD) and muscle atrophy F-box (MAFbx-1) in the rectus femoris. Compared with those of Group C, in Groups I and U, total contracture, myogenic contracture, MyoD and MAFbx-1 levels were significantly elevated, and CSA was significantly smaller ( p < 0.05). Compared with those of Group I at each time point, MyoD levels were significantly elevated, MAFbx-1 levels were significantly lower, CSA was significantly larger, and myogenic contracture was significantly alleviated in Group U ( p < 0.05). In the early stages of contracture, ultrashort wave diathermy reduces muscle atrophy and delays the process of myogenic contracture during joint immobilization; the mechanism of this may be explained as increased expression of MyoD triggered by suppression of the MAFbx-1-mediated ubiquitin-proteasome pathway.

Role of hypoxia-mediated pyroptosis in the development of extending knee joint contracture in rats

“…In order to observe the natural process of joint contracture, we established an animal model using immobilization by aluminum plates. Joint contracture is characterized by a reduction of joint range of motion compared with normal joints [ 34 , 35 ], thus decreased join range of motion represents increased degree of joint contracture. Previous studies have suggested that joint contracture occur within 1 week of knee joint immobilization and progress in a time-dependent manner [ 36 , 37 ].…”