科研之友
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摘要
It is widely described in the literature that diabetic patients present hearing impairment. Despite the histological alterations of the internal ear structures in these patients as well as in experimental models of diabetes, to the best of our knowledge, an histological evaluation of the vestibulocochlear nerve have not been performed. In the present study, ultrastructural alterations are described and compared between a spinal nerves and a cranial nerve in rats with chronic induced diabetes. Male Wistar rats (n = 12), fed with standard diet from the animal care facility at 42 days of age were used. Induced diabetic animals (n=6) were fasted for 12 hours prior to being injected intraperitoneally with streptozotocin (STZ - 60mg/kg) in a single dose. Control animals (n=6) received (0.01 mol/l citrate buffer, pH 4.5) vehicle alone. Ten weeks after STZ injection the animals were perfused intracardially with Karnovsky solution. Right and left vestibulocochlear nerves were dissected and histologically processed for epoxy resin embedding. Samples were imaged with the transmission electron microscope. Large myelinated fibers with morphological signs of axonal atrophy in the vestibulocochlear nerves were readily observed. These results suggest that chronic STZ-induced diabetes in rats caused alterations in the myelinated fibers and Schwann cells, compatible to the classic diabetes signs and symptoms. Morphological alterations of the vestibulocochlear nerve in diabetes is described for the first time and contributes information for a better understanding of why there are changes in hearing observed in diabetic patients. Se ha descrito ampliamente en la literatura que los pacientes diab谷ticos presentan discapacidad auditiva. En estos pacientes, a pesar de las alteraciones histol車gicas de las estructuras del o赤do interno, as赤 como en modelos experimentales de diabetes, que mejoran nuestro conocimiento, la evaluaci車n histol車gica del nervio vestibulococlear no ha sido realizada. Se describen y comparan las alteraciones ultraestructurales entre un nervio espinal y uno craneal en ratas con diabetes cr車nica inducida. Fueron utilizadas 12 ratas Wistar machos, de 42 d赤as de edad, alimentadas con dieta est芍ndar. Los animales diab谷ticos inducidos (n = 6) se mantuvieron en ayuno por 12 horas antes de ser inyectados por v赤a intraperitoneal con estreptozotocina (STZ - 60mg/kg) en una sola dosis. Los animales control (n = 6) s車lo recibieron inyecci車n de 0.01 mol/l buffer, citrato pH 4,5. Diez semanas despu谷s de la inyecci車n de STZ, los animales fueron perfundidos intracardiacam
