Characterization of the variety on cross sectional area, capillary density and neonatal myosin expression in the masseter and temporalis muscle / Caracterização da variação do calibre das fibras musculares, densidade capilar e expressão de miosina neonatal nos músculos masseter e temporal

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Temporomandibular disfunction (TMD) is a colletive term that refers to different clinical problems of the temporomandibular joint and the jaw muscles. These disfunctions are characterizied meanly by pain, joint sounds and irregular or limited mandibular function. The jaw muscles can be involved in the TMD of muscle etiology, and by definition they are the ones which provide the teeth touch, then the jaw elevators: masseter, temporalis, medial pterygoid and lateral pterygoid. As the muscular etiology is the most prevalent cause of TMD, the detailed understanding of structural and functional composition of the masticatory muscles is paramount to better comprehend TMD due to muscle disorder. This study has the aim to analyze the jaw muscle structure concerning capillarie density, neonatal myosin expression, and the cross sectional area of the fast and slow fibers in temporalis and masseter muscles in autopsy samples from 1st to 9th decades of age. Thirty seven temporalis and masseter muscles samples were studied (20 from male and 17 from female) from Serviço de Verificação de Óbitos of São Paulo. The specimens were divided by gender and ages. The samples were collected up to 18 hours post-mortem. Imunohistochemistry stainning were made with antibodies to analize the protein expression. The evaluations were made by two observers, after intra observer calibration (two evaluations on the same field by the same observer in different times) and inter observer (evaluation of the same field by two observers), unti getting less than 10% of error. The number of capillaries per fiber in the masseter and temporalis muscle was in average 1 and 0,7 respectively. The number of capillaries per mm² was significantly higher in the masseter when compared to temporalis muscle (p=0.025). The neonatal myosin was present in all decades in both muscles, and it was observed that the cross sectional area of the type II fibers was smaller than the type I fibers

ASSUNTO(S)

capillary cadeias pesadas de miosina capilares músculos mastigatórios masticatory muscle myosin heavy chain

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