Repeated noise exposure disrupts hippocampal-dependent behavior in adolescent male and female rats: Can environmental enrichment protect?

Adolescence is a critical period for brain maturation, during which the hippocampus (HC) may be particularly vulnerable to environmental factors. Noise exposure has been associated with HC-related cognitive and behavioral alterations, but the effects of repeated exposure during adolescence, particularly in females, remain poorly understood. Environmental enrichment (EE) has shown protective effects against noise. This study evaluated repeated noise exposure effects on HC-related behaviors and the protective role of EE in adolescent rats of both sexes. At postnatal day (PND) 21, Wistar rats were housed in standard cages or EE. From PND28, a subgroup was exposed to white noise (95–97 dB, 2 h/day) for five days. Inhibitory avoidance, elevated plus maze, and open field tests were performed. Noise impaired contextual associative memory, increased grooming and exploration, and reduced risk assessment in both sexes, as well as anxiety-like behaviors in females. EE prevented grooming and risk assessment changes, while reducing anxiety-like behaviors and increasing exploration in both sexes. Noise exposure in EE-housed rats produced additional behavioral changes. Overall, repeated noise exposure affected several HC-related memory and behavioral responses in both sexes, while EE exerted modulatory effects with limited preventive efficacy. These findings suggest that repeated noise exposure may produce substantial behavioral alterations that could limit the protective effects of EE.