Behavioral and neuroanatomical effects on exposure to White noise in rats.

Noise pollution is a severe public health problem as continuous exposure to even moderate noise levels between 55-65 dB can lead to various pathologies, including neurological states. In the present study, we assessed the ultrastructural alterations in selective auditory pathways of the rat brain following high intensity white noise exposure. In addition, learning, anxiety-like behavior and locomotor activity were assessed. Adult male rats were exposed to 100 dB noise, one hour daily, for 10 consecutive days. The evaluations were performed on day 11. Exposure to noise did not affect learning or the components of locomotor activity. However, it induced anxiety-like behavior as evidenced by time spent in the closed arm of elevated-plus maze. Concomitantly, ultrastructural changes in medial geniculate body, considered an integral component of classical auditory pathway, as well as in the hippocampus and basolateral amygdala, considered important structures of non-classical auditory pathway were noted. Specifically, noise resulted in neuronal apoptosis, chromatolysis, cytoplasmic organelle destruction, and glial activation in medial geniculate body and hippocampus, as well as mild alterations in amygdala. These results provide further evidence of detrimental consequences following exposure to loud noise.