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Age-related hearing loss (AHL) –presbycusis– is the number one neurodegenerative disorder and top communication deficit of our aged population. Experimental evidence suggests that mitochondrial dysfunction associated with reactive oxygen species (ROS) plays a central role in the aging process of cochlear cells. Dietary antioxidants, in particular polyphenols, have been found to be beneficial in protecting against the generation of ROS in various diseases associated with oxidative stress, such as cancer, neurodegenerative diseases and aging. Objectives This study was designed to investigate the effects of polyphenols on AHL and to determine whether oxidative stress plays a role in the pathophysiology of AHL. Methods Sprague-Dawley rats (n = 100) were divided into five groups according to their age (3, 6, 12, 18 and 24 months old) and treated with 100 mg/kg/day body weight of polyphenols dissolved in tap water for half of the life of the animal. Auditory steady-state responses (ASSR) threshold shifts were measured before sacrificing the rats. Then, cochleae were harvested to measure total superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, reactive oxidative and nitrogen species levels, superoxide anions and nitrotyrosine levels. Results Increased levels of ROS and RNS in cochlea observed with age decreases with polyphenol treatment. In addition, the activity of SOD and GPx enzymes in older rats recovered after the administration of polyphenols. Conclusion: The reduction in oxidative and nitrosative stress in the presence of polyphenols correlates with significant improvements in ASSR threshold shifts.

Resumen El cancer escamoso de cabeza y cuello se caracteriza por su tendencia a la invasion local y a distancia, ademas de una alta predisposicion a la aparicion de segundas neoplasias. El proceso de invasion y metastasis es complejo y tiene multiples etapas. Las metaloproteinasas de matriz 2 y 9, se sobreexpresan en el cancer escamoso de cabeza y cuello donde actuan degradando la membrana extracelular favoreciendo asi la invasion tumoral y la metastasis. El bacilo de Calmette-Guerin (BCG) ha sido usado como inmunomodulador en el tratamiento de algunos tipos de cancer con buenos resultados. El proposito de este estudio es determinar el efecto de la activacion inmune mediada por el BCG sobre la migracion e invasion usando un modelo in vitro 3 D de cultivos de celulas tumorales de faringe cocultivadas con celulas mononucleares de sangre periferica en contacto o no con el BCG. Para determinar la expresion de las metaloproteinasas y p53 se realizo Western blot y para la migracion e invasion, kits comerciales. Los resultados muestran disminucion en la expresion de metaloproteinasas, p53 y en la migracion en el grupo BCG.