Effects of acute and chronic stress on masseter muscle in masticatory hypofunction

• Grant number: 11/00856-7
• Support Opportunities: Regular Research Grants
• Duration: May 01, 2011 - August 31, 2013
• Field of knowledge: Biological Sciences - Morphology - Anatomy
• Principal Investigator: Mamie Mizusaki Iyomasa
• Grantee: Mamie Mizusaki Iyomasa
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: Christie Ramos Andrade Leite Panissi ; João Paulo Mardegan Issa ; Pedro Duarte Novaes ; Raquel Fernanda Gerlach

Abstract

The patient who suffered dental occlusion losses present a collapse that affects the stomatognathic functions. Although, stress is involved in the pathogenesis of chronic diseases and enable the masticatory muscle pain in patients, it remains poorly understood the mechanism by which muscle adapts to physiological and psychological stresses. This study will investigate the effect of acute and chronic stress in masseter muscles of animals not submitted to unilateral extraction by morphologic, immunohistochemical, histochemical, total gelatinolytic activity, and myeloperoxidase evaluation. It will be used 70 male Wistar rats, young adult, weighing on average 200g that were randomly divided into two groups: Group Malocclusion (GM) - animals exposed to unilateral exodontia and stress protocols (n = 35) and Group without Malocclusion (GSM) - animals without extraction protocols and exposed to stress (n = 35). In each group, it will have the following subgroups, with n = 5 each: I - no stress at 14 days; II - acute stress; III - chronic stress repeated; IV: varied chronic stress ; V: no stress at 25 days. The animals of malocclusion (GM)group will be submitted to unilateral extraction of left upper molars, under anesthesia with intraperitoneal xylazine (10mg/kg) and ketamine (70mg/kg). In both groups: GM and GSM, the animals of subgroups II, III and IV will be submitted to protocols stress from the 14th day after the extraction. The animals of subgroups I and II, both the GSM and the GM, will be euthanized on the 14th. After the initial experimental period, the animals of subgroups II, IV and V of both groups will be euthanized at 25 days after beginning of the experiment. The results allow to assess if the various types of stress influence on the fibers morphology, the density of capillaries in the contractile fibers in the oxidative metabolism and the inflammatory muscle. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

IYOMASA, MAMIE MIZUSAKI; FERNANDES, FERNANDA SILVA; IYOMASA, DANIELA MIZUSAKI; LARA PEREIRA, YAMBA CARLA; RESTREPO FERNANDEZ, RODRIGO ALBERTO; CALZZANI, RICARDO ALEXANDRE; NASCIMENTO, GLAUCE CRIVELARO; ANDRADE LEITE-PANISSI, CHRISTIE RAMOS; MARDEGAN ISSA, JOAO PAULO. Metabolic Changes in Masseter Muscle of Rats Submitted to Acute Stress Associated with Exodontia. PLoS One, v. 10, n. 6, JUN 8 2015. (11/00856-7, 11/15209-7, 11/18889-9)