Moderate noise exposure differentially affects hippocampal and auditory structures in developing rats.

URAN S. L.; AON L.; PELEGRINO F.; CACERES L.G.; CAPANI F.; GUELMAN L.R.

Congreso; XXVI Reunión Anual de la Sociedad Argentina de Investigación en Neurociencias (SAN), Huerta Grande, Córdoba, Argentina, 20-22 de octubre de 2011.; 2011

Noise is one of the causative factors of hearing loss. However, the vulnerability of the auditory system to different noise levels seems to be variable. On the other hand, noise can also affect extra-auditory areas such as the hippocampus (Hip). Therefore, the aim of this work was to elucidate if exposure to moderate noise induces histological and functional changes in the auditory pathway. Since hippocampal-related behavioral changes were found in noise-exposed rats, hippocampal histological assessment was made to investigate if potential auditory changes could underlie Hip alterations. Male Wistar rats of 15 days were exposed to white noise (95-97 dB, 2h/day) and separated into acute (AE, 2h/day) and chronic exposure (CE, 2h/day for 15 d) groups. The integrity of the auditory pathway was evaluated by recording auditory brainstem response (ABR). Histological assessment of cochlea and Hip was also performed. Results showed no significant differences in ABR in noise-exposed rats, without changes in cochlear histology. In contrast, histological changes were found in Hip of exposed rats. These data suggest that AE and CE to moderate noise are capable of inducing hippocampal histological impairments in developing rats, without affecting auditory function and morphology.