Effects of acute stress in the lateral pterygoid muscle in masticatory hypofunction

Abstract

Clinical evidence suggests that emotional stress can be a risk factor for periodontal disease, as well as other functions performed by the stomatognathic system. However, no studies on possible changes in the masticatory muscles in subjects undergoing stress. The objective of this project is to evaluate the hypothesis that acute stress induces morphophysiological changes in left lateral pterygoid muscle in animals not submitted to unilateral exodontia. This muscle was chosen because it is intimately involved in the execution of the movements of opening and closing the mouth, needed for proper performance of the masticatory cycle. Will be used 20 male Wistar rats (250g) were randomly divided into two major protocols: Malocclusion (GM): exposed to unilateral extraction (n = 10), and No Malocclusion (GSM) without extraction unilateral (n = 10). Each protocol will consist of two subgroups (n = 5 mice each): I: Acute Stress, II: no stress (stress control). The GM will be submitted to unilateral extraction of molars left under anesthesia with 4% association of xylazine (10mg/kg) and 10% ketamine (80mg/kg) ip In both groups: GM and GSM, the rats of subgroup I are subjected to acute stress protocols on the 25th day after the extraction. With the end of the experiments, the animals will be euthanized to obtain muscles for analysis by techniques: morphological, immunohistochemical and histochemical. The results allow to assess whether acute stress causes changes in the morphology of the fibers, the density of the capillaries in the contractile capacity of the fibers, and the production of reactive oxygen species (ROS) as well as in sensitivity orofacial. (AU)