NOISE-INDUCED RAT HIPPOCAMPAL OXIDATIVE CHANGES WERE INVERTED AFTER REARING IN AN ENRICHED ENVIRONMENT.

S. J. MOLINA, M. MICELI, F. CAPANI, L. R. GUELMAN

Congreso; Society of Neurocience meetig; 2016

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NOISE-INDUCED RAT HIPPOCAMPAL OXIDATIVE CHANGES WERE INVERTED AFTER REARING IN AN ENRICHED ENVIRONMENTIt is well known that noise exposure can induce transient or permanent hearing loss. However, few data are available regarding its effects on extra-auditory structures, mainly within developing Central Nervous System. Previous studies of our laboratory showed that exposure of immature rats (7 and 15-days-old) to moderate noise during 2 hours, can induce hippocampal-related behavioral alterations that differ depending on the age of exposure. Moreover, rearing these animals in an enriched environment (EE) has shown to be an effective protective tool which almost fully prevented noise-induced behavioral changes.Therefore, the aim of the present work was to test if noise exposure at different ages might generate hippocampal changes in an oxidative marker such as Trx-1. The potential prevention of these changes through the use of an enriched environment (EE) was also assessed.Rats of 7 and 15 days were exposed during 2 h to white noise (95-97 dB) for one day. After weaning, groups of 3-4 rats were transferred to an enriched cage, consisting of toys, a wheel, tunnels and ramps, while other groups were placed in standard cages. After one week, levels of Trx-1, a member of the family of the antioxidants thioredoxins, were evaluated.Results showed that Trx-1 levels of rats exposed at 7 days and reared in standard cages were increased, whereas no significant changes were found in rats reared in EE when compared with their respective control animals. In contrast, animals exposed at 15 days showed no significant differences in Trx-1 levels, neither in standard nor in enriched conditions.These findings suggest that noise exposure at several developmental ages might differentially affect hippocampal oxidative status. The restoration of hippocampal Trx-1 levels in exposed animals reared in an EE might be correlated with a more reduced cellular milieu facilitated by EE rearing, suggesting that this strategy could be useful to aid animals to cope with an unfavorable condition.