LOUD NOISE EXPOSURE AFFECTS DIFFERENTLY HIPPOCAMPAL AND AUDITORY STRUCTURES IN DEVELOPING RATS

URAN, SL; AON BERTOLINO, L; PELLEGRINO, F; CACERES, LG; CAPANI, F; GUELMAN, LR

Huerta Grande, Córdoba

Congreso; III Reunión Conjunta de Neurociencias (IRCN); 2011

Sociedad Argentna de Investigación en Neurociencias

Noise is the greatest causative factor of hearing loss. Despite this, the vulnerability of the auditory system of different animal models to loud noise is very variable. Acoustic contamination can also affect extra-auditory areas of the Central Nervous System such as the hippocampus (Hip). The aim of the present work was to elucidate if the exposure to loud noise during the rat developmental period induces histological and/or functional changes in the auditory pathway and to establish the role of potential hippocampal damage. Male Wistar rats of 15 days were exposed to white noise (95-97 dB, 2h/day) and separated into two groups, acute (AE, 2h/day) and chronic exposure (CE, 2h/day for 15 d). The integrity of the auditory pathway was evaluated by obtaining auditory brainstem response (ABR) thresholds at 30-days-old rats. Histological assessments of the cochlea and Hip were also performed. Results showed that there were no significative differences in ABR in rats exposed to loud noise. This data are consistent with histological results. Otherwise histological changes were found in hippocampal pyramidal cell layers in noise-exposed rats. Results suggest that AE and CE to loud noise are capable of inducing hippocampal impairments in developing rats, but not produce auditory dysfunction at a post-exposure time of 30 days.