Rearing immature rats in an enriched environment can prevent the behavioral alterations induced by early noise exposure

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

Montreal

Congreso; 20th Biennial Meeting of the International Society for Developmental Neuroscience and the 5th Annual NeuroDevNet Brain Development Conference; 2014

International Society for Developmental Neuroscience

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 exposure of immature rats to moderate noise for two hours can induce hippocampus (HC)-related behavioral, biochemical and histological alterations, including changes in anxiety-like behaviors. However, potential strategies of neuroprotection have not been explored yet. Interestingly, 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 white noise for two hours, using an ?ad-hoc? sound camera. After weaning, groups of 3-4 rats were transferred to an enriched cage, consisting of different toys, a wheel, plastic tunnels and ramps. Other groups were placed in standard cages. One week later, different behavioral tests were performed, 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 developmental age, other behavioral changes were observed, mainly related with decreased anxiety-like behaviors (increased time in center in the OF, increased time in open arms in the EPM), that could be interpreted as a maladaptive behavior. Rearing in EE almost fully prevented anxiety-related changes. These findings suggest that visual, social and/or physical stimulation during the peri-adolescence period, after exposure to a physical agent such as noise, might contribute to stabilization of normal emotional behavioral parameters.