Trabalho de Conclusão de Curso

Documento

Autoria

Malzone, Bruno Lima

Unidade da USP

Data de Apresentação

Orientador

Guimaraes, Elaine Aparecida Del Bel Belluz

Título em Inglês

Positive effects of benzodiazepine therapy on masticatory muscle dysfunctions induced by chronic stress in a rodent model of occlusal instability

Palavras-chave em Inglês

Stress
Masticatory dysfunction
Benzodiazepine
Medial pterygoid muscle
Transmission electronic microscopy
Metabolism

Resumo em Inglês

Psychological stress and occlusal alteration are important etiologic factors for temporomandibular/masticatory muscular disorders, but the exact physiologic mechanism underlying this relation remains unclear. Our purpose was to test the hypothesis that benzodiazepine therapy is able to prevent metabolic and vascular changes in the medial pterygoid muscle of rats under chronic stress and unilateral exodontia. Adult Wistar rats were submitted to unpredictable chronic mild stress and/or unilateral exodontia and their plasma and medial pterygoid muscles were removed for analysis. A pre-treatment with diazepam was used to verify its effect on stress. The parameters evaluated included anxiety behavior, plasma levels of corticosterone, metabolic activity by succinate dehydrogenase, capillary density by laminin staining and ultrastructural findings by transmission electron microscopy. Occlusal instability induced anxiety-like behavior on elevated plus-maze test and diazepam administration blocked the appearance of this behavior. Unilateral exodontia promoted in the contralateral muscle an increase of oxidative fibers and capillaries and modification of sarcoplasmatic reticulum. Chronic stress caused increased glycolytic metabolism, reduced capillary density and morphological changes in mitochondria on both sides. Association of both factors induced a glycolytic pattern in muscle and hemodynamic changes. Pharmacological manipulation with diazepam inhibited the changes in the medial pterygoid muscle after stress. Our findings provide insights into the mechanisms by which chronic stress and exodontia might be involved in the pathophysiology of masticatory muscular dysfunctions, possibly inducing metabolic and capillary alterations, and shows, for the first time, an effective preventive benzodiazepine treatment for stress and occlusal instability conditions affecting masticatory muscle disorders

Arquivos

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Data de Publicação

2020-02-07

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