Effects of repeated chronic stress in masseter muscle under masticatory hypofunction

• Grant number: 11/15209-7
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): March 01, 2012
• Effective date (End): June 30, 2013
• Field of knowledge: Biological Sciences - Morphology - Anatomy
• Principal Investigator: Mamie Mizusaki Iyomasa
• Grantee: Ricardo Alexandre Junqueira Calzzani
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Stresses of repeated nature seem to foster hyperalgesia and allodynia. In fact, clinical evidence has shown that physical and emotional stress may be associated with altered masticatory muscle function in subjects submitted to different daily situations. However, descriptions of morphological changes in masticatory muscles induced by occlusal alteration and associated with emotional stress are still scarce in the literature. The aim of this study is to investigate the effect of chronic stress in the masseter muscle of animals subjected or not to unilateral extraction, through morphological, immunohistochemical and histochemical assessment, total gelatinolytic activity and myeloperoxidade. Twenty male Wistar rats, young adult, weighing on average 200g will be divided randomly into two groups: Malocclusion group (MG): rats were exposed to unilateral extraction (n = 10) and Control group (CG): rats without extraction ( n = 10). Groups will be further divided in the following subgroups (n = 5 each): (I) repeated chronic stress (II) no stress. The extraction of left upper molars will be performed under intraperitoneal anesthesia with 4% Xylazine (10mg/kg) and 10% ketamine (80mg/kg). For both MG and CG, the rats of subgroup I will be subjected to repeated chronic stress protocols from the 14th day after the extraction. During the experimental period the animals will be weighed and then the masseter muscle will be collected for analysis by the HE, Immune, MET, SDH, NADH, ROS, MPO, and GT techniques, and the results will allow to assess the influence of repeated chronic stress associated with malocclusion in the morphology of the fibers, the density of capillaries in the contractile fibers in the oxidative metabolism and muscle inflammation. (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)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

CALZZANI, Ricardo Alexandre Junqueira. Morphophysiological effects of chronic stress and exodontia in the masseter muscle of rats. 2013. Master's Dissertation - Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC) Ribeirão Preto.