The Influence Of Shortwave Therapy And Static Magnetic Field Effect On Myoatrophy In Rabbits After Immobilization

Objectives: To investigate the influence of shortwave therapy and static magnetic field effect on myoatrophy and joint contracture in rabbits after immobilization. The experimental model for osteoarthritis was developed by periodic immobilization of rabbit knees.Methods: 35 male white rabbits were made the skeletal muscle atrophy and joint contracture models by fixing left knee joints on extensive position. There are 35 knees. When the models are successful, the 35 white rabbits were randomly divided into 5 groups. Group A is the normal group without any treatments, group B was immobilized group without any therapy, group C received static magnetic field therapy, group D received shortwave therapy,group E received shortwave therapy and static magnetic field therapy. The groups all had been treated for 6 weeks. The range of motion were measured before and after treatment. At the end of the 6 weeks, all rabbits were killed, the quadriceps femoris were researched by VG-staining haematoxylin-eosin staining and immunohistochemical techniques in order to know the changes of diameter and cross section area of muscle fiber and observe the expression of Bcl-2, the staining of the glycosaminoglycan portion of cartilage and know the results of histological and histochemical scoring system. Results: 1.Passive Range of Motion (PROM): The five groups had no significant differences among them before treatment (P>0.05). The change of PROM had significant differences between group A, group B ,group D and group E (P<0.05). However , there was no significant differences between group B and group C (P>0.05).2.The changes of diameter and cross section area of muscle fiber:there are significant differences between group A, group B, group C ,group and group E (P<0.05).3.The appearance of VG-staining:there are significant differences of fibrosis extent between group A , group B, group C ,group D and group E (P<0.05).4. The positive expression rate of Bcl-2: there are significant differences between group A, group B, group C, group D and group E (P<0.05).Conclusions: Shortwave therapy can all prevent the process of myoatrophy,so that it can reduce and prevent the process of joint contracture, but the static magnetic field therapy didn't have obvious effect on preventing the joint contracture.