Lipopolysaccaride (LPS) a known neuro-inflammatory agent and bilirubin share significant similarities in their gene activation profile and both cause a rise in auditory threshold.

A) Whole genome gene expression analysis was carried out on brain tissue following bilirubin or LPS exposure. The top 100 genes with the greatest fold changes across all datasets are shown. Up-regulated genes are shown in red and down-regulated genes in blue. The values represent log2 fold change compared to control samples (n = 4). Samples and genes were clustered using the Euclidean distance algorithm. B) The ABRs from a mouse are shown before LPS injection and C) 4h after LPS injection in the same animal. ABR responses are displayed over volume range of 35 to 90 dB (SPL), with the trace at threshold indicated in red. In this paired data LPS clearly raised auditory thresholds. D) Average data are plotted as Mean±SEM auditory thresholds, shown before and after LPS injection; LPS significantly increased auditory threshold (39±2 dB SPL for control n = 5 vs 50 dB ±7 dB SPL after LPS n = 4, p = 0.014, t test).