Effect of ultrashort wave treatment on joint dysfunction and muscle atrophy in a rabbit model of extending knee joint contracture: Enhanced expression of myogenic differentiation.

ABSTRACT

OBJECTIVE: To investigate the effects of ultrashort wave treatment on joint dysfunction and muscle atrophy in a rabbit model of extending knee joint contracture. METHODS: Forty rabbits were randomly divided into eight groups. In group C, the left knee joint was not fixed. In group I-8, the left knee joint was only fixed for eight weeks. In groups R-1, R-2, and R-4, the left knee joint was fixed for eight weeks before the rabbits underwent one, two, and four weeks of self-recovery, respectively. In groups T-1, T-2, and T-4, the left knee joint was fixed for eight weeks before the rabbits underwent one, two, and four weeks of ultrashort wave treatment, respectively. The degree of total contracture and myogenic contracture were measured, the cross-sectional area (CSA) and protein levels for myogenic differentiation (MyoD) of the rectus femoris were evaluated. RESULTS: There was a tendency toward a reduced degree of total and myogenic contracture, and also a tendency toward an increased CSA of the rectus femoris and increased protein levels for MyoD after both self-recovery and ultrashort wave treatment. The ultrashort wave was more effective than self-recovery in reducing the total and myogenic contracture, and increasing the CSA and MyoD protein levels of the rectus femoris. CONCLUSIONS: Ultrashort wave treatment may ameliorate joint dysfunction and muscle atrophy by upregulating the expression of MyoD protein in a rabbit model of extending knee joint contracture.