Effect of acute noise trauma on the gene expression profile of the hippocampus.

<bold>Background: </bold>This study aimed to investigate the changes in the expression of hippocampal genes upon acute noise exposure.<bold>Methods: </bold>Three-week-old Sprague-Dawley rats were assigned to control (n = 15) and noise (n = 15) groups. White noise (2-20 kHz, 115 dB sound pressure level [SPL]) was delivered for 4 h per day for 3 days to the noise group. All rats were sacrificed on the last day of noise exposure, and gene expression in the hippocampus was analyzed using a microarray. Pathway analyses were conducted for genes that showed differential expression ≥ 1.5-fold and P ≤ 0.05 compared to the control group. The genes included in the putative pathways were measured using quantitative reverse transcription-polymerase chain reaction (qRT-PCR).<bold>Results: </bold>Thirty-eight upregulated genes and 81 downregulated genes were identified. The pathway analyses revealed that upregulated genes were involved in the cellular responses to external stimuli and immune system pathways. qRT-PCR confirmed the upregulation of the involved genes. The downregulated genes were involved in neuronal systems and synapse-related pathways, and qRT-PCR confirmed the downregulation of the involved genes.<bold>Conclusions: </bold>Acute noise exposure upregulated the expression of immune-related genes and downregulated the expression of neurotransmission-related genes in the hippocampus. [ABSTRACT FROM AUTHOR]