Effect of acute and chronic restraint stress in the medial pterygoid muscle of rats with and without partial edentulism

acute stress is an important protective response, while chronic stress, isolated or accompanied by occlusal instability, is a risk factor for masticatory muscle disorders. This work studied the metabolic and vascular alterations provoked by acute and chronic restraint stress in the medial pterygoid muscle of rats with and without unilateral exodontia. The plasmatic levels of corticosterone, metabolic activity, oxidative capacity, capillary density, and production of reactive oxidative species were analyzed. The corticosterone levels, as well as the number of fibers from SDH and NADPH, and capillary density were statistically significant showing p values < 0.05. Restraint stress increased the oxidative metabolism and capillary density in the medial pterygoid muscle. Exodontia promoted a glycolytic transformation of muscle fibers. These hemodynamic and metabolic changes may explain the pathogenic mechanisms of masticatory muscle disorders. This work provides evidence of metabolic and hemodynamic changes in a masticatory muscle caused by stress and partial edentulism.