فهرست نشریات علمی دسترسی آزاد ایران

Aim: This study aimed to quantitatively assess the expression changes of muscle damage biomarkers (troponin, myoglobin, and creatine kinase) in masticatory muscles following mandibular advancement and during a recovery phase, providing insights into the molecular mechanisms of functional adaptation.Methods: Thirty male Wistar rats (6–8 weeks old) were divided into three groups: control (no appliance), experimental (mandibular advancement appliance for 30 days), and recovery (appliance for 30 days followed by 30 days without appliance). After the intervention, masticatory muscles (masseter and lateral pterygoid) and mandibular condyles were harvested. Sandwich ELISA was used to quantify biomarker expression, while histomorphometric analysis was applied to assess muscle fiber diameter and condylar cartilage thickness changes. One-way ANOVA, Tukey’s post hoc test, Kruskal-Wallis and Mann-Whitney U test with Bonferroni correction, were applied for statistical analyses. P<0.05 was considered as significant.Results: Troponin levels increased significantly (23.8%, P=0.020) in the lateral pterygoid muscle of the experimental group compared to controls while remaining elevated (16.2%, P=0.140) during recovery. Myoglobin expression showed muscle-specific responses, with significant increases in masseter muscle (11.3%, P<0.001) during recovery. Creatine kinase levels varied significantly between groups (P<0.001) in the masseter muscle. Histologically, lateral pterygoid muscle exhibited greater hypertrophy than masseter muscle. Condylar cartilage showed increased proliferative layer thickness during appliance wear and enhanced hypertrophic layer development during recovery.Conclusion: Forward positioning of the mandible leads to increased expression of troponin, creatine kinase, and myoglobin in the masseter and lateral pterygoid muscles.The differential expression of biomarkers between muscle groups suggests muscle-specific adaptation mechanisms, providing new insights into the biological basis of orthodontic treatment outcomes and stability.