RESUMO
Recent focus has been given on the effects of high-intensity infrasound (HII) exposure, and whether it induces changes in pancreatic morphology and glucose metabolism is still unknown. As such, we have studied the impact of HII exposure on glucose tolerance, insulin sensitivity, pancreatic islet morphology, muscle GLUT4 and plasma insulin and corticosterone levels. Normal and glucose intolerant wild-type Wistar rats were randomly divided in two groups: one group not exposed to HII and the other continuously exposed to HII. Animals were sacrificed at three timepoints of exposure (1, 6 or 12 weeks). An intraperitoneal glucose tolerance test was performed, blood samples were collected and the pancreas and the quadriceps femoris muscle were excised. Circulating insulin and corticosterone levels were determined and pancreatic and muscular tissue were routinely processed for histochemistry and immunohistochemistry with an anti-GLUT4 antibody. Animals exposed to HII had higher corticosterone levels than animals not exposed. No differences were found on insulin concerning HII exposure or glucose intolerance. Glucose intolerant animals had pancreatic islet fibrosis and no differences were found in GLUT4 ratio concerning HII exposure. In conclusion, we found that continuous exposure to HII increases stress hormone levels without inducing glucose intolerance in rats.
Assuntos
Glicemia/metabolismo , Intolerância à Glucose/metabolismo , Glucose/metabolismo , Resistência à Insulina , Som , Animais , Corticosterona/sangue , Transportador de Glucose Tipo 4/metabolismo , Imuno-Histoquímica/métodos , Insulina/sangue , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Masculino , Músculo Esquelético/metabolismo , Ratos WistarRESUMO
INTRODUCTION: Low-frequency noise (LFN) is a ubiquitous physical stressor known to cause degenerative cellular changes and organ alterations with functional repercussions both in humans and animals. MATERIALS AND METHODS: After acceptance of the study protocol by a local ethics committee, 20 Wistar rats were randomly divided into two equal groups. One group was kept in silence and the other continuously exposed to LFN during 13 weeks. The rats had unlimited access to water and were fed standard rat chow. After exposure, the animals were sacrificed and the parotid glands were excised and prepared for transmission electron microscopy. RESULTS: The acinar cells showed marked ultrastructural alterations, such as intracellular vacuolization, loss of cell polarity, increased heterochromatin, cytoplasmic inclusions, and oncocytic transformation. CONCLUSIONS: LFN induces ultrastructural changes in the rat parotid gland that correlate with previously described functional changes.