ENRICHED ENVIRONMENT IS ABLE TO COUNTERACT SOME OF THE HISTOLOGICAL ALTERATIONS INDUCED BY EARLY NOISE EXPOSURE

MOLINA, SJ; SAINT-MARTIN, M; CAPANI, F AND GUELMAN, LR

Montreal

Congreso; 20th Biennial Meeting of the International Society for Developmental Neuroscience,; 2014

It is known that acute noise exposure can induce transient or permanent hearing loss. However, few data are available regarding its effects on extra-auditory structures, in particular within developing Central Nervous System (CNS). Previous studies of our laboratory showed that expo sure of immature rats to moderate noise for two hours can induce hippocampus (HC)-related behav ioral, biochemical and histological alterations, including changes in anxiety-like beha viors. However, potential strategies of neuroprotection have not been explored yet. Interes tingly, rearing animals in an enriched  environment has shown to be an effective protective non-pharmacological tool against different CNS injuries. Therefore, the aim of the present work was to test if enriched environment housing (EE) can prevent noise-induced behavioral changes.  Fifteen-days-old rats were exposed to 95-97 dB of w hite noise for two hours, using an ?ad-hoc? sound camera. After weaning, groups of 3-4 rats wer e transferred to an enriched cage, consisting of different toys, a wheel, plastic tunn els and ramps. Other groups were placed in  standard cages. One week later, different behavioral tests were per formed, including open field (OF), elevated plus maze (EPM) and inhibitory avoidance (IA) tasks . Results show that whereas no changes in associative memory or habituation memory were  found in rats exposed to noise at an early develop cental age, other behavioral changes were observed, mainly related with decreased anxiety-lik e behaviors (increased time in center in the OF, increased time in open arms in the EPM), that c ould be interpreted as a maladaptive  behavior. Rearing in EE almost fully prevented anxi ety-related changes. These findings suggest that visual, social and/or p hysical stimulation during the periadolescence period, after exposure to a physical ag ent such as noise, might contribute to stabilization of normal emotional behavioral parame ters.   Keywords: Noise, Enriched environment, anxiety-like behavior