Effect Of Functional Applicance On The Differentiation Of Myoblast And The Activity Of NF-κB In Juvenile Rats After Functional Mandibular Protrusion

ObjectiveThe circumstance of skeletal muscle growth is complex, not only by the role of force in different ways, but also by nerve and various cytokines. Research at the cellular and molecular level will help to elucidate the important signaling pathway, which mechanical factors regulate the differentiation of myoblast, and is expected to reveal the mechanism of the mechanical signaling pathway with activation from the view of cross talk between the different signaling pathways. The purpose of this study is to explore the lateral pterygoid muscle in adolescent rats subjected to stress stimulation in the growth (remodeling) reflected at the cellular level, so as to provide new ideas and experimental basis in functional orthopedic treatment and treatment effects retention, and has far-reaching scientific significance and potential values. This new area has not yet been concluded. In addition, the mechanical environment of the expression of myoblasts in-depth understanding and studies, can provide a theoretical basis for mechanical stimulation to cure the muscular dystrophy, meanwhile can provide reference in prevention effective, treatment aggressive and rehabilitation reasonably for skeletal muscle injury associated with the movement.MethodsIn our experiment,4 weeks old,20 male SD rats were randomly divided into 8 groups. The experimental group were anesthetized by pentobarbital wearing maxillary inclined plane, the control group not to wear. According to different periods of time, rats were divided into four groups:Id,7d,14d,21d.1. Technical analysis differentiation-related genes MyoD, myogenin mRNA expression changes by RT-PCR in juvenile rats lateral pterygoid muscle after functional mandibular protrusion.2. Detected the expression of p65 in nucleoprotein of lateral pterygoid muscle by western-blotting.Immunofluorescence staining of NF-κB p65 subunit is translocate into the nucleus to confirm whether the NF-κB signaling pathway is activated.Results1. Expression of MyoD in lateral pterygoid muscle tissue is decreasing when the rats are growth, and myogenin upregulation occurred in the 14d group. The expression of MyoD in the 7d experimental group was significantly increased. Meanwhile, the expression of myogenin in lateral pterygoid muscle tissue of experimental group under stress increased compare to control group in same condition.2. Immunofluorescence staining results show rats, which is treatment by functional orthopedic force, the expression of NF-κB p65 significantly higher than those without treatment. Prompting p65, a major subunit of NF-κB, have translocated into nucleus to judge NF-κB has been activated.3. Western blotting shows the nucleoprotein of lateral pterygoid muscle tissue in experimental group was detected p65 expression downregulation, while rats in the control group are stable.Conclusions1. Functional orthopedic force on lateral pterygoid muscle tissue can induce the expression of MyoD and myogenin mRNA increased, and in turn induce the differentiation of myoblast.2. Lateral pterygoid muscle tissue under the stretch can induce the p65 translocate to nucleus and then regulate the transcription of target genes. 3. The activation of p65 which induced by stretch may inhibited the differentiation of myoblast.